Centre Special Research Photovoltaics 1999...Photovoltaics Special Research Centre finishing at the end of1999, the group was successful in obtain-ing support for a new ARC Special

1999

Photovoltaics

Special Research

Centre

UUNNSSWW

1999

Photovoltaics

Special Research

Centre

The University of New South Wales

Centre for Photovoltaic Engineering

Electrical Engineering Building


UNSW SYDNEY NSW 2052

AUSTRALIA

Tel+61 2 9385 4018 Fax+61 2 9662 4240

E-mail: [email protected] http://www.pv.unsw.edu.au

Annual Report

UUNNSSWW

� ii iii �

ContentsThe 1999 Annual Report contains three sections which are colour coded as follows:

Red: Photovoltaics Special Research Centre End-of-Grant Report . . . . . . . . . . . . . . . . . . . . . .S1

Orange: Photovoltaics Special Research Centre1999 Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PV1

Green: Special Research Centre for Third Generation PhotovoltaicsStart-Up Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T1

� iv v �

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE

area of science and technology pro-

moting human welfare. They were

the first all-Australian team to win

the award since 1992.

Best Paper Awards,SapporoFollowing on from the best paper

award it received at the 2nd World

Conference on Photovoltaic Solar

Energy Conference in Vienna in

1998, the Centre also fared well at

the next major international confer-

ence in the field, the 11th

International Photovoltaic Science

and Engineering Conference in

Sapporo, Japan in September, 1999.

A best paper award was presented

to Jianhua Zhao, Aihua Wang and

Martin Green for their paper on

high efficiency solar cells. Their

work involving international collab-

oration in exploring the effect of

different silicon preparation meth-

ods also won a special award, jointly

with the Fraunhofer Institute for

Solar Energy Systems, Germany

and Tokyo University of Agri-

culture and Technology, Japan.

New Centre forAdvanced CellsWith the 9-year grant period for the

Photovoltaics Special Research

Centre finishing at the end of 1999,

the group was successful in obtain-

ing support for a new ARC Special

Research Centre in Third Gen-

eration Photovoltaics which com-

menced in January, 2000. This

Centre will have a more restricted

scope than the Photovoltaics Special

Research Centre, seeking to develop

a new generation of thin-film cell of

efficiency much closer to the limit-

ing performance possible for the

conversion of sunlight to electricity

(93%). More details are contained in

this Centre's start-up report at the

rear of this volume.

Pacific Solar Trial MarketingCentre spin-off, Pacific Solar,

entered a new phase of develop-

ment with the trial marketing of

residential photovoltaic systems in

the Sydney area. The new systems

featured a new mounting structure

developed by Pacific Solar.

Although presently using imported

module-level inverters and solar

laminates, the company plans to

include its own inverter into such

systems in 2000 and the Centre's

silicon-on-glass thin-film technolo-

gy in 2003. Two other licensees, BP

Solar and Solarex, announced the

formation of the combined BP

Solarex during the year, now clearly

the world's largest photovoltaic

manufacturer.

1999 Australia Prize In February, Centre Directors

Martin Green and Stuart Wenham

were presented with the Australia

Prize by Prime Minister John

Howard in a special ceremony in

Parliament House in Canberra. The

Prize is an international award for

specific achievement in a selected

PERL CELL.

Silicon Cell World Records

Two new world records for silicon solar cell performance

were established by the Centre during 1999. A new out-

right record of 24.7% energy conversion efficiency was

demonstrated together with a new record of 24.5% for a

cell made on a substrate other than one prepared by the

float-zone process.

New Directors To take up the Directorship of thenew Centre for Third GenerationPhotovoltaics, Professor MartinGreen resigned from the Director-ship of the Photovoltaics SpecialResearch Centre at the end of 1999.The new Directors are Dr JianhuaZhao, Dr Christiana Honsberg, andDr Armin Aberle with responsibili-ties for the areas indicated on theaccompanying photographs.

PACIFIC SOLAR ROOFTOP.

DR ARMIN ABERLE

DIRECTOR (THIN FILM)

Aurora 101 Wins World Solar Challenge

Using high performance solar cells manufactured by the

Centre, the Australian solar car, Aurora 101, won the

1999 World Solar Challenge, the major international

solar car race along the 3,000 kilometer course from

Darwin to Adelaide. This follows the Centre's success in

the previous event in 1996, where the Honda Dream

won convincingly using Centre cells. Early in the race's

history, the Spirit of Biel also won using cells made

under license to the Centre, giving the Centre 3 wins

from the 5 races so far.

1 9 9 9 H I G H L I G H T S

1999 Highlights1999 Highlights

PROFESSOR MARTIN GREEN (LEFT), THE PRIME MINISTER,

JOHN HOWARD AND PROFESSOR STUART WENHAM.

DR JIANHUA ZHAO

DIRECTOR (HIGH EFFICIENCY)

DR CHRISTIANA HONSBERG

DIRECTOR (BURIED CONTACT)

vii �� vi

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE D I R E C T O R ’ S R E P O R T

The final year of operation

continued the success of ear-

lier years with notable

achievements in both “first-

generation” silicon wafer-

based research and in “sec-

ond-generation” thin-film

solar cell development. As

detailed in the end-of-grant

report that follows, the

Centre surpassed its original

two aims relating to both

these generations of solar cell

technology. It also comfort-

ably exceeded its third aim of

stimulating research activities

in the photovoltaic systems

and applications area.

Highlights during the grant peri-

od have been the on-going

improvements in “first-genera-

tion” silicon solar cell efficien-

cy, with a further improve-

ment to a record 24.7% effi-

ciency posted during 1999.

BP Solarex also successful-

ly commercialised the

Centre’s “buried contact”

cells during the grant

period, with these

becoming the cells pro-

duced in the highest

volume in Europe over

recent years.

The highlight in the

area of “second-gen-

eration” thin-film technol-

ogy has been the establish-

Australia across all disci-

plines. This Centre has activ-

ities clearly differentiated

from the Photovoltaics

Special Research Centre and

the Key Centre for Photo-

voltaic Engineering, concen-

trating on a “third-genera-

tion” of photovoltaic tech-

nology, not yet fully con-

ceived, let alone implement-

ed. I will be the Director of

this new Centre with Dr

Armin Aberle, Deputy

Director. Dr Aberle will have

special responsibilities for

the new Centre’s experimen-

tal programs.

The new Centre will attempt

to develop ideas, able to be

implemented in thin-film

form, likely to significantly,

rather than incrementally,

improve photovoltaic cell

performance beyond that of

a single junction device.

Tandem stacks of solar cells

and Dr Armin Aberle as the

new Directors. These would

be responsible for continuing

the High Efficiency, Buried

Contact and Silicon Thin-Film

strands of the original Centre,

respectively. Each of these

areas is at, or close to, the

forefront of international

activity in these areas. Funding

for these activities will be

sought through a variety of

sources, including competitive

grants schemes.

May I take this opportunity to

thank those who have con-

tributed to the past success of

the Photovoltaics Special

Research Centre. We are enter-

ing an exciting period for pho-

tovoltaics. I hope we will be

able to build on past successes,

to help accelerate the wide-

spread adoption of this new,

benign and sustainable energy

generation technology.

of differing bandgaps are

probably the best known

example of such a third-gen-

eration approach, whereby

efficiency can be increased

merely by serially stacking

more cells. The new Centre

will explore approaches capa-

ble of similar efficiency but

using more innovative “paral-

lelled” approaches. More

information on the new

Centre and some of the ideas

it intends to explore can be

found in the “start-up”

report at the rear of the pres-

ent publication.

Finally, although I have re-

signed as its Director, an on-

going role for the original

Photovoltaics Special Re-

search Centre has been

approved. Approval has been

gained for the continuation of

the Centre and its world-lead-

ing research with Dr Jianhua

Zhao, Dr Christiana Honsberg

ment of Pacific Solar Pty Ltd,

specifically to commercialise

the Centre’s work in this area.

This initiative forms the basis

of one of the largest invest-

ments in renewable energy in

Australian history, as well as

one of the largest industry-

university commercialisation

projects.

Perhaps the greatest success in

the systems area relates to the

photovoltaic project for the

athletes’ village for the Sydney

2000 Olympics. This has been

assessed as the major environ-

mental success of these

“Green Olympics”. Many of

the parties involved in this

project gained their initial

experience with photovoltaics

via contact with the Centre, in

addition to the direct role

played by the Centre in its con-

ception and implementation.

Undoubtedly aided by the

achievements of the Photo-

voltaics Special Research

Centre, the University was

successful in its application

for a similar ARC Special

Research Centre in Third

Generation Photovoltaics.

The Centre, which com-

menced in January, 2000, is

one of a small number of

such Centres selected from

applications from around

Director’s Report

PROFESSOR MARTIN GREEN,FOUNDING DIRECTOR,PHOTOVOLTAICS SPECIAL RESEARCH CENTRE

At the end of 1999, the Photovoltaics Special Research

Centre completed the maximum 9-year period of support

from the Australian Research Council.

� Sviii

Photovoltaics Special

Research Centre

End-of-Grant Report

Photovoltaics Special

Research Centre

End-of-Grant Report

T A B L E O F C O N T E N T S

S3 �

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S4

Aims and Outcomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S8

Device Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S12

Supporting Fundamental Work . . . . . . . . . . . . . . . . . . . . . . . . . . . .S18

Systems Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S20

Education, Training and Technology Transfer . . . . . . . . . . . . . . . .S21

External Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S22

Financials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S23

Publications (1991 -1999) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .S24

Table of ContentsTable of Contents

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT S U M M A R Y

S5 �� S4

The Photovoltaics Special Re-

search Centre was established in

1991 with support from the

Australian Research Council

(ARC) Research Centres Sch-

eme. At this time, it was one of

a small number of Centres

selected from all disciplines

around Australia after extensive

review. The Centre was initially

funded for a period of 6 years,

subject to review during 1993.

The Centre was reviewed again

in 1996 with the result that the

period of ARC funding was

extended to the end of 1999,

completing the maximum 9 year

period for Special Research

Centre funding. ARC funding

was approximately AU$1 mil-

lion/year (US$600,000/year)

over this period, although this

was supplemented by income

from other sources. The ARC

funds accounted for approxi-

mately 40% of the funds avail-

able for Centre related activities.

The original aims of the Centre

were maintained over its 9 year

funding period. The three origi-

nal aims were:

� To maintain and extend

Australia’s lead with convention-

al silicon solar cells and develop

these cells to their full potential;

� To develop silicon “thin film”

technology based on depositing sil-

icon onto glass and to be involved

with one or more commercial col-

laborators with associated technol-

ogy transfer by 1996;

� To develop a co-ordinated set of

activities in the photovoltaics sys-

tem area, with these to be funded

largely from other sources.

The original aims have been

fully met and, in some cases,

substantially exceeded. The

Centre has maintained a clear

advantage with conventional or

“first generation” silicon cell

performance over its life. With

the confirmation of 24.7% cell

efficiency during 1999, the

advantage over the next best

result internationally has been

extended to over 5% (relative),

compared to a more modest 3%

advantage when the Centre

commenced, despite significant

overall improvements during

this period. Another notable

result was the demonstration of

19.8% efficiency on a multicrys-

talline silicon wafer during 1998,

establishing an even greater

margin over the next best result

internationally in this area.

Apart from these performance

advantages, other achievements

in work related to the first of

the above aims are noteworthy.

These include the successful

commercialisation of the Uni-

The third aim has also been

comfortably exceeded with the

diversion of only a small frac-

tion of the ARC grant as seed-

ing funds for this purpose. The

University is now widely recog-

nised for its photovoltaic sys-

tems activities, receiving major

support from Pacific Power,

EnergyAustralia, Australian aid

agencies and the Australian Co-

operative Research Centre for

Renewable Energy (ACRE) for

this work over the grant period.

Highlights include the installa-

tion of the first grid-connected

photovoltaic systems in New

South Wales at the University's

Solar Research Facility at Little

Bay, the establishment of a

Design Assistance Division to

provide advice, not otherwise

readily available, to prospective

users of photovoltaic systems;

the development and running of

accreditation courses for the

Solar Industries Association of

Australia; acting as a focus for

the development of standards

for inverters for grid-connected

photovoltaic systems; working

with various parties in connec-

tion with providing photovoltaic

power to each of the more than

600 homes comprising the

Athletes’ Village for the Sydney

2000 Olympics; and the running

of a variety of courses including

the first international internet

courses on photovoltaic devices

and systems. Independent con-

firmation of the quality of this

systems work comes from a best

paper award, “Best in Terrestrial

Applications Area” at the 1st

World Conference on Photo-

voltaic Energy Conversion in

Hawaii in December, 1994, an

invited plenary session paper for

system researcher, Dr Muriel

Watt, at the 26th IEEE Photo-

of 34 postgraduate research the-

ses were successfully completed

by Centre students, with 22 of

these at the doctoral level. The

Centre has published several

textbooks on photovoltaics that

are the most widely used in this

field, internationally, amongst

other achievements in the aca-

demic area. A summary of

notable outcomes is given in

Table S1.

voltaic Specialists Conference in

Washington in May, 1996, the

most highly rated systems paper

in the international journal

“Progress in Photovoltaics”

over the 1993-1995 period, and

several best paper awards in this

area at local conferences.

The Centre has also had notable

success in other areas not direct-

ly related to the three specific

aims above. For example, a total

versity’s buried contact technol-

ogy by BP Solarex during the

grant period. This has now

become the most successfully

commercialised new solar cell

technology over this period.

Similar success has been enjoyed

in commercialising other Centre

“first generation” cell technolo-

gy for use on spacecraft. A relat-

ed result has been the success

enjoyed by Centre cells in solar

car racing, with Centre cells on

the winning car in three of the

four major international solar

car races held during the

Centre’s life.

Achievement of the second aim

relating to the development of a

“second generation” of silicon

thin-film technology may prove

even more important to the

photovoltaics field in the long

term. In 1994, the Centre

announced the filing of patent

applications on a new cell struc-

ture suitable for use on low

quality, silicon thin-films, such

as could be deposited onto glass.

This attracted international

media coverage and was hailed

as a “conceptual breakthrough”

at the time. The new develop-

ment stimulated the largest

investment to date in renewable

energy technology in Australian

history, by local utility, Pacific

Power, to evaluate the commer-

cial potential of this approach.

A new company, Pacific Solar,

was formed in 1995 to perform

this evaluation. The company

successfully commenced pilot-

production of silicon-on-glass

thin-film modules in 1998 and

plans to have product on the

market by 2003, comfortably

exceeding the original Centre

objectives.

SummarySummaryDirector:

Professor Martin Green (to 12/99)

Associate Directors:

Dr Armin Aberle (Thin-Film Devices) (from 11/98)

A/Professor Paul A. Basore (Multilayer Technology Commercialisation) (from 11/95 to 12/99)

Dr Christiana Honsberg (Buried Contact Cells) (from 1/99)

A/Professor Hugh R. Outhred (Systems)

Professor Stuart R. Wenham (Devices) (to 12/98)

Dr Jianhua Zhao (High Efficiency Cells) (from 1/99)

1999 24.7% efficient silicon solar cell*

24.5% efficiency cell on non-FZ substrate*

Aurora 101 solar car wins World Solar challenge with UNSW cells

1998 19.8% efficient “honeycomb textured” multicrystalline cell*

24.5% efficiency silicon solar cell*

1997 18.2% efficient planar multicrystalline solar cell

22.7% efficient solar module*

1996 22.3% efficient solar module*

23.7% efficient large area cell (22 cm2)

1995 17.6% multijunction solar cell (32 microns active thickness)

1994 Development of multijunction solar cell

24.0% efficient silicon solar cell*

15.2% multijunction solar cell (20 microns active thickness)

720 mV silicon cell*

Development of rear floating junction devices with record voltages

1993 20.6% solar module* (first flatplate module to exceed 20% efficiency)

21.6% efficient large area cell (46 cm2)*

1992 717 mV silicon cell*

19.9% solar module*

1991 600 mV, 10% efficient thin film silicon cell (low T deposition)

TABLE S1: OUTCOMES

(PHOTOVOLTAICS SPECIAL RESEARCH CENTRE)

DEVICE RESEARCH (*DENOTES WORLD BEST)

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � EENNDD-OOFF-GGRRAANNTT RREEPPOORRTT S U M M A R Y

S7 �� S6

1999 Australia Prize awarded to Directors, Martin Green and Stuart Wenham

IEE Sir Lionel Hooke Award (M.A. Green)

Best Paper Award “Silicon Cells”, 11th Int. PV Conf., Hokkaido (J. Zhao et al.)

Special Award, International Collaboration, 11th Int. PV Conf., Hokkaido

1998 Overall Best Poster Award, 2nd World PV Conference, Vienna (M. Green)

Best Poster, “Fundamentals, Novel Devices, New Materials”, Vienna (M. Green)

Chairman’s Award, Australian Technology Awards

1997 Australian Achiever Award (M. Green)

Best Paper Award, Solar ’97 (P. Rowley et alia)

Best Student Paper, Solar ’97 (D. Remmer)

1995 IEEE J.J. Ebers Award “sustained technical leadership”, Washington (M. Green)

M.A. Sargent Medal “contributions through innovation” (M.A. Green)

Special Mention, Centre Posters at 13th European PV Conf., Nice

1994 Clunies Ross National Science and Technology Award (M. Green)

Best Poster, “Terrestrial Applications”, 1st World PV Conf., Hawaii

(M. Watt et al.)

1992 CSIRO External Medal (M. Green and S. Wenham)

EXTERNAL AWARDS

COMMERCIAL OUTCOMES

1999 Buried-contact technology transfer (Eurosolare)

1998 Pacific Solar announces pilot line commissioning (thin film cells)

BP Solar announces 20 MW, $57M plant in Sydney (buried contact cells)

Eurosolare licenses buried-contact technology

1995 Pacific Solar commences operation

Buried-contact cell most successfully commercialised in last 15 years

1994 Samsung licenses buried-contact technology

Thin-film on glass technology assigned to Pacific Solar

1993 550 kW system at Toledo, Spain using licensed technology

(world’s most efficient large PV system)

1992 First large system using licensed UNSW technology

(24 kW system using BP Solar modules in Berne, Switzerland)

1991 BP Solar releases “Saturn” module under licence

(highest efficient commercial module)

A I M S A N D O U T C O M E S

S9 �

development of the approach. A

new company, Pacific Solar, began

operation in Sydney in February,

1995 for this purpose. This exceeded

the initial Centre targeted timeline by

more than a year and addressed the

issue with much greater urgency

than originally contemplated. The

company began pilot production of

pilot line modules in 1998 (Figure

S4). In the same year, it was awarded

the Chairman's Award at the

Australian Technology Awards for

its efforts. The company presently

plans to have the new technology

commercially available by 2003.

The third aim of

the Centre lay in

the systems or

applica-

tions

a r e a .

The Centre

has successfully

achieved its goal

if greatly stimulating

these activities, while com-

mitting only quite modest

seeding funds for this purpose.


� S8

Aims

The original aims of the

Centre were maintained

over its 9 year life. The

three aims were:

� To maintain and extend

Australia’s lead with conven-

tional silicon solar cells and

develop these to their full

potential;

� To develop silicon “thin film”

technology based on deposit-

ing silicon onto glass and to be

involved with one or more

commercial collaborators with

associated technology transfer

by 1996;

� To develop a co-ordinated set

of activities in the photo-

voltaics system area with these

to be funded largely from other

sources.

OutcomesThe Centre achieved its first aim

by extending its international

lead with first-generation, silicon

wafer based technology. By

demonstrating 24.7% efficiency

during 1999, the Centre exceed-

ed its international lead to over

5% relative, compared to 3% at

the commencement of the

Centre. The best confirmed effi-

ciencies from groups in Europe,

Japan and the United States at

present are 23.3%, 23.5% and

22.7% efficiency, respectively.

In the multicrystalline silicon cell

area, the Centre established a

value of 19.8% in 1998, more

than 6% relative above the next

best result internationally of

18.6%, established by the Centre

of Excellence in Photovoltaic

Research at the Georgia Institute

of Technology.

In the area of packaged modules,

the Centre established a new world

mark of 22.7%, well above the

next best result of 21.6% estab-

lished by the Honda Corporation

of Japan working with Sunpower

Corporation of the United States.

race record in the 1996 World

Solar Challenge, the solar car

race across Australia. Powered

only by Centre cells, the car aver-

aged 90 km/hr across the 3,000

km course. Other solar cars that

have won the Challenge using

Centre cells included the Spirit

of Biel and Aurora 101, with

Centre cells used on the

Aims and OutcomesAims and OutcomesSunrayce, where competitors were

restricted to inexpensive commercial

cells, 9 of the 10 top cars were pow-

ered with cells made under licence to

the Centre. The sixth placed car not

using Centre cells won a special award

for doing so well with such a handi-

cap. In the next race, competitors

were restricted to US-made cells to

broaden the supply base, since the

cells supplied by BP Solarex were

unique in performance.

During the life of the Centre, BP

Solarex successfully commercialized

first-generation Centre technology.

Figure S1 shows the first large instal-

lation of these cells at the Spanish

utility, Union Fenosa, site near Toledo

in 1994. At the time, this was

Europe's largest photovoltaic system.

Over recent years, the cells made in

highest volume in Europe have been

made under license to the Centre. In

1998, BP Solarex announced plans

for establishing the world's largest

solar cell manufacturing facility in

Sydney (Figure S3). With the subse-

quent merger of BP and Amoco,

these plans have been shelved,

although European production of

Centre cells is being expanded.

Other commercialisation success

has been with cells manufactured

for use on spacecraft. Cell tech-

nology first demonstrated by the

Centre has now been commer-

cialised by Tecstar Corporation

of California and the Sharp

Corporation of Japan. An

Australian consortium also com-

pleted a feasibility study of space

cell manufacture and array

assembly in Australia using

Centre cell technology.

Considerable success has also been

achieved with more recently devel-

oped second-generation technolo-

gy, involving the deposition of very

thin films of silicon onto glass sub-

strates. After showing that the main

challenge in this area was deposit-

ing films of the quality required for

good cell performance, the Centre

announced the filing of patents on

a new cell structure able to tolerate

low quality material. This attracted

international attention at the time,

being hailed as a “conceptual

breakthrough” and featuring in the

New York Times, Time Magazine,

Scientific American and a range of

other newspapers and magazines.

The new cell designs gave

a high level of confidence

in the viability of the

silicon thin-film

approach. This

resulted in a

major initia-

tive by Aus-

tralian utility,

Pacific Power, to

fund the commercial

FIGURE S2: HONDA DREAM SOLAR CAR.

FIGURE S1: CENTRE DIRECTOR, MARTIN GREEN,

AT EUROPE'S THEN LARGEST PHOTOVOLTAIC PLANT IN TOLEDO,

USING CELLS MADE UNDER LICENSE TO THE CENTRE.

FIGURE S3: ARTIST'S IMPRESSION OF THE PROPOSED BP SOLAREX

FACILITY IN SYDNEY (ARTWORK COURTESY OF BP SOLAREX)

FIGURE S4: PACIFIC SOLAR PILOT LINE MODULE

(PHOTOGRAPH COURTESY OF PACIFIC SOLAR PTY LTD).

This clear lead in cell perform-

ance has been used to advantage

in solar car racing. Figure S2

shows the Honda Dream, the

best performing solar car to

date, that set an as yet unbeaten

winning car in three of the five

Challenges to date.

Even greater success in this area

has been enjoyed by Centre licens-

ee, BP Solarex. In the 1993

A I M S A N D O U T C O M E S

S11 �


� S10

The University is now widely recog-

nised for its photovoltaic systems

activities, receiving major support

from Pacific Power, Energy-

Australia, Australian aid agencies

and the Australian Co-operative

Research Centre for Renewable

Energy (ACRE) for this work over

the present reporting period.

Highlights include the installa-

tion of the first grid-connected

photovoltaic systems in New

South Wales at the University's

Solar Research Facility at Little

Bay. This has now been operat-

ing satisfactorily for many years.

Another highlight has been the

establishment of a Design

Assistance Division to provide

advice, not otherwise readily

available, to prospective users of

photovoltaic systems. Major

installations in which it has

played a role include a 4 kilowatt

hybrid system installed by

National Parks and Wildlife on

Montague Island, off the New

South Wales coast, a 4 kW

hybrid system at Green Cape

National Park on the New South

Wales far south coast, as well as

many smaller projects. The

Centre has also participated in

the development and running of

accreditation courses for the

Solar Industries Association of

Australia. It has also acted as a

focus for the development of

standards for inverters for grid-

connected photovoltaic systems,

working with various parties in

connection with providing pho-

tovoltaic power to each of the

more than 600 homes compris-

ing the Athletes' Village for the

Sydney 2000 Olympics. The

Centre has also developed and

run a variety of short courses

including the first international

internet courses on photovoltaic

devices and systems.

Independent confirmation of the

quality of this systems work stim-

ulated by the Centre comes from

a best paper award in “ Terrestrial

Applications Area” at the 1st

World Conference on Photo-

voltaic Energy Conversion in

Hawaii in December, 1994, an

invited plenary session paper for

system researcher, Dr Muriel

Watt, at the 26th IEEE Photo-

voltaic Specialists Conference in

Washington in May, 1996, the

most highly rated systems paper

in the international journal

“Progress in Photovoltaics” over

the 1993-1995 period, and several

best paper awards in this area at

local conferences (see Table S1).

D E V I C E R E S E A R C H

S13 �

record” 24.7% with the PERL

cell approach, another key result

of the Centre was the demon-

stration of 19.8% efficiency on

low cost multicrystalline sub-

strates supplied by the Italian

company, Eurosolare. A striking

feature of these cells was the

use of a “honeycomb” texture

(Figure S6) to play the same role

as the “inverted pyramids” in

the crystalline cells (the latter

technique could not be used

with multicrystalline silicon due

to the lack of a well defined ori-

entation template). Another fea-

ture of multicrystalline silicon

cells is the spatial non-uniformi-

ty of cell response. This is

demonstrated in Figure S7

where the different colours

show regions of different

response of the 19.8% efficient

cell due to crystallographic

defects, particularly grain

boundaries.

Other key results in this high-

efficiency cell strand of activity

include the demonstration of

Buried ContactSolar Cells

Project Leader:

Dr Christiana Honsberg

Other Contributors:

Dr Benjamin Chan, Dr Chee Mun Chong,

Dr Jeff Cotter, Dr Ximing Dai,

Dr Kerrie Davies, Dr Ebong Abesafreke,

Dr Sean Edmiston, Alan Fung,

Seyed Ghozati, Professor Martin Green,

Amal Khouri, Linda Koschier,

Keith McIntosh, Dr Hamid Mehrvarz,

Stephen Pritchard, Bryce Richards,

Jiqun Shi, Alexander Slade, Yinghui Tang,

Dr Michael Taouk, Bernhard Vogl,

Professor Stuart Wenham, Yan Wu,

Rudong Xiao, Fei Yun,

Dr Fuzu Zhang, Dr Jianhua Zhao,

With the success of BP Solarex in

commercializing the buried contact

cell, this cell became the most success-

fully commercialized new solar cell

technology over the grant period. The

cell structure, shown in Figure S9, was

developed as an attempt to incorpo-

rate some of the high efficiency

features demonstrated in the previous

high efficiency strand of the work

into a low cost commercial cell.

the first 20% efficient photo-

voltaic module from any materi-

al in 1993. This was subsequent-

ly increased to 22.7% in 1996 by

the use of the innovative cell

shingling approach.

Other highlights include the

fabrication of large quantities of

high performance solar cells for

both the 1993 and 1996 World

Solar Challenges, the major

international solar car race from

Darwin to Adelaide. For the

1996 event, almost 20,000

PERL cells were fabricated with

cell efficiency ranging up to

24%. Figure S8 shows the cell

efficiency distribution accumu-

lating after each month of pro-

duction during 1996. The graph

shows a steady refinement in the

performance of the cells as

more experience was gained

with the manufacture. Over 60%

of the cells demonstrated

efficiencies above 23%. Most

of these cells are higher in

performance than those made in

any laboratory around the world

giving the Centre the record for

the best 10,000 silicon cells

ever made!


� S12

High EfficiencyCells

Project Leader:

Dr Jianhua Zhao

Other Contributors:

Dr Armin Aberle

Dr Pietro Altermatt

Dr Shijun Cai

Dr Ximing Dai

Professor Martin Green

Yinghui Tang

Dr Aihua Wang

Professor Stuart Wenham

The PERL (passivated emitter,

rear locally-diffused) cell of

Figure S5, first successfully

implemented during the early

years of the Centre's operation ,

has been the mainstay for most of

the improvements demonstrated

during the life of the Centre.

Key electronic features are the

almost complete enshroudment of

the cell in a thermally grown oxide

to give the lowest possible rates of

surface recombination, the use of

small area contacts to reduce

metal-semiconductor recombina-

tion rates, the use of highly doped

diffused regions in these contact

regions for the same purpose, and

the selection of processing condi-

tions to ensure the preservation or

even enhancement of material

quality, as measured by minority

carrier lifetime. Particular attention

has been given to the quality of the

oxide-silicon interface with an

atomic hydrogen treatment giving

best results to date. This treatment

is based on the local generation of

this atomic hydrogen by reaction

of hydrogen ions in the oxide with

an aluminum capping layer.

Optically, the inverted pyramids on

the top surface reduce reflection

loss. Light is also coupled in

obliquely across the cell, increasing

prospects for absorption for weak-

ly absorbed wavelengths. The

metal rear contact serves as an effi-

cient reflector of light reaching the

rear, particularly when displaced by

the low refractive index oxide layer,

as shown. After rear reflection,

weakly absorbed light approaches

the top surface from within the

cell, with about half striking pyra-

mid faces that couple it out. The

rest strikes other pyramid faces at

angles that are sufficiently oblique

that this light is reflected by total

internal reflection. This light is

very effectively “trapped” into the

cell. Optically, this makes the cell

appear much thicker than its actual

thickness - up to 40 times thicker

for some of the Centre's experi-

mental devices.

The effectiveness of this “light

trapping” approach was demon-

strated by another key result

from the Centre. This was the

demonstration of 21.5% effi-

ciency for a cell that was only 48

microns thick, almost 10 times

thinner than the Centre's normal

high performance devices. This

provides experimental support

for the view that such “light trap-

ping” allows reasonable per-

formance to be obtained from

silicon films that are much thin-

ner than previously thought

feasible.

Apart from increasing silicon

cell efficiency to a “world

Device ResearchDevice Research

FIGURE S5: PERL SILICON SOLAR CELL.

FIGURE S6:

HONEYCOMB TEXTURING OF

MULTICRYSTALLINE CELL.

FIGURE S8: EFFICIENCY DISTRIBUTION OF PERL CELLS FOR

1996 WORLD SOLAR CHALLENGE.

FIGURE S7:

SPATIAL RESPONSE OF

19.8% EFFICIENT MULTI-

CRYSTALLINE CELL.

S15 �

ticrystalline silicon wafers. For

low quality wafers, the perform-

ance benefit of the standard

selective emitter feature of the

buried contact cells becomes

less important because the cell

open-circuit becomes dominat-

ed by recombination in the bulk

regions of the cells rather than

at the contacts.

Work with the simplified

sequence has shown that open

circuit voltage in excess of 650

mV is achievable without the

use of the selective emitter dif-

fusion compared to values

approaching 700 mV with this

diffusion. A key element of the

simplified sequence is the use of

titanium dioxide, not only as an

antireflection coating but also as

a plating mask. Figure S10

shows experimental results

showing the use of titanium

dioxide with an underlying thin

silicon dioxide layer (13.5 nm)

allows surface recombination

velocities using this coating con-

sistent with open circuit voltage

in excess of 650 mV.


� S14

Independent studies have shown that

this is not only the highest efficiency

cell in production, but is also the low-

est in cost under a similar set of eco-

nomic assumptions when compared

to use this technology (Figure S3).

Unfortunately, the merger of BP

and Amoco was announced shortly

after which resulted in these plans

being shelved.

Work during the reporting period

concentrated on two issues. One

was the simplification of the

buried contact sequence to allow

it to be more compatible with

solar cell processing lines based

on the existing cell technology.

The second was based on improv-

ing the performance of the rear

contact of the buried contact

solar cell to bring its performance

to a level where it more closely

matched that of the PERL cells.

The first-mentioned simplified

buried contact sequence uses a

number of innovations in the

processing sequence to reduce

the cost of fabrication while

retaining the efficiency advan-

tages of the buried contact tech-

nology. It is designed especially

for lower quality wafers such as

Czochralski grown and mul-

In the double-sided solar cell

sequence, a similar processing

sequence is applied to the rear

of the cell to bring its perform-

ance to a level consistent to that

of the top half of the cell

(Figure S11).

This structure proved more dif-

ficult to implement than expect-

ed due to the unanticipated

effects of shunt resistance upon

the rear cell performance. It was

realised that these were more

severe than in a standard solar

cell due to the lower effective

current densities attributable to

the rear contact. Extensive com-

puter modelling allowed these

effects to be fully understood

and experimental work made

significant progress towards

implementing high efficiency

devices. For example, solar cells

fabricated on high resistivity

wafers (5 �cm) demonstrated

voltages in excess of 650 mV

when illuminated from either

the front or rear surface. The

current response when illumi-

nated from the rear was 94% of

that when illuminated from the

front, a very high ratio for such

a simply fabricated cell. Use of

buried contacts on both front

and rear surface allowed mini-

mal obscuration of the cell sur-

face by these contacts. These

results demonstrate that a high

efficiency bifacial cell, using this

double sided structure, is techni-

cally feasible although still not at

the stage where it can be reliably

implemented commercially.

A second approach was also

explored as a way of improving

the rear contact to the cell. This

made use of a novel selective

solid phase epitaxial regrowth

process on the rear surface. This

project is now the subject of a

collaborative agreement with BP

Solarex and is being continued

as part of the program of the

Key Centre for Photovoltaic

Engineering (see separate Key

Centre Annual Report for a

more detailed account).

Another highlight in the buried

contact cell area was the fabrica-

tion of over 10,000 large area

buried contact solar cells for the

1993 World Solar Challenge. This

initiative made use of the pilot

line for buried contact cell fabri-

cation that had been established

for technology transfer to

licensees. An enhanced sequence

that combined the buried contact

top cell design with a photolitho-

graphically processed rear surface

contact resulted in cells being

fabricated with efficiencies up to

21.3%. Sixteen of these cells

were encapsulated locally into a

standard module by the former

Solarex Pty. Ltd. to produce a

world record efficiency of 19.8%

for a photovoltaic module.


FIGURE S9: BURIED CONTACT SOLAR CELL.

FIGURE S10: EMITTER SATURATION CURRENT DENSITY MEASURED ON

MULTICRYSTALLINE WAFERS FOR VARIOUS SURFACE COATINGS. THE SOLID

LINES ARE SIMULATED WITH PC1D WITH THE INSET NUMBERS REPRESENT-

ING SURFACE RECOMBINATION VELOCITY. THE RED, PURPLE AND GREEN

SYMBOLS REPRESENT EXPERIMENTAL MEASUREMENTS OF SILICON DIOXIDE,

TITANIUM DIOXIDE, AND TITANIUM DIOXIDE OVER A THIN (13.5 NM)

SILICON DIOXIDE PASSIVATING LAYER, RESPECTIVELY.

FIGURE S11: DOUBLE-SIDED BURIED CONTACT SOLAR CELL.

to other wafer-based cell technologies

(T. Bruton, et alia, Conf. Record, 14th

European Photovoltaic Solar Energy

Conference, Barcelona, June/July,

1997, p. 11).

During the life of the Centre, the

first commercial installation of these

cells was installed on the funicular

railway leading to the Parliament

House in Berne, commissioned in

1992. The next large application was

for the Union Fenoza 1 MW plant in

Toledo, which was Europe's largest

photovoltaic installation at the time

(Figure S1). This was officially

opened in mid-1994. Since then, the

production output of the cells has

been greatly expanded at the

expense of more conventional tech-

nology previously used by BP

Solarex. An announcement was

made in late 1998 indicating the

imminent commissioning of the

world's largest solar cell manufactur-

ing facility here in Sydney which was


S17 �

of silicon films. Shown in Figure S13are results for thin films prepared bythe Centre by sputtering, both beforeand after solid phase crystallization.Similar techniques were applied tomaterial produced by Pacific Solarunder a contract between the Centreand the company.

Another notable achievement was thedevelopment of electron-beam in-duced current (EBIC) technique forcharacterising experimental devices.Figure S14 shows this technique com-bined with electron microscopy toexplore grain boundary properties inmultilayer cells.

The third phase of activity hasinvolved the initiation of thin-filmprograms independent of the PacificSolar program. Good success has beenobtained with the metal induced crys-tallization of films deposited ontoglass. This is quite an unusual sequencein that, as shown in Figure S15, thedeposition sequence involved firstdepositing a layer of aluminum ontoglass and then a layer of similar thick-ness of amorphous silicon. After heat-ing for a short period, about 30 min-utes, at moderate temperatures around500o C the aluminum and siliconchange place as illustrated. Moreover,the originally deposited amorphous sil-icon layer is converted to large grainpolycrystalline material. This producescrystallites with very large lateraldimensions (typically above 20microns) which is unusual for the verylow processing temperatures involved.

The silicon layers are heavily dopedwith aluminum which reduces theirelectronic quality. Although it may bepossible to fabricate devices directlyinto these layers, work was also conducted that uses these layers as seeding layers for subsequent epit-axial growth of better quality siliconmaterial.

Another phase of activity involved thelaser crystallization of amorphous sili-con using copper vapour lasers. The

extremely high resolution that isachievable.

Fourier transform infrared spec-troscopy (FTIR) has also been devel-oped to allow characterisation of thesefilms. The technique is suitable fordetermining the hydrogen concentra-tion in these films as well as the filmthickness and refractive index as well asthe bonding configuration in amor-phous and polycrystalline silicon and insilicon nitride films deposited on sili-con wafers.

A more recent program is concernedwith careful documentation of theadvantages of the multilayer approachcompared to more traditional cellstructures. Multilayer cells are fabricat-ed using epitaxially grown layers oninert silicon wafer substrates. Con-ventional devices are grown by thesame approach. The performance isthen compared as a function of mate-rial quality, where this is adjusted bydamaging material by high energy pro-ton radiation. This allows the advan-tage of the buried contact approach tobe quantified as a function of materialquality. The clear advantage of themultilayer cell has become apparentduring this work. Due to the presenceof multiple junctions, a larger fractionof the volume of the cell remainsactive even when material quality isextremely poor.

use of excimer laser crystallization ofsilicon films is well established in theactive matrix liquid crystal display area.The films used in the latter application,however, are too thin for use in photo-voltaics where layers of several micronthickness are required. The wavelengthof the copper vapour laser is muchmore suited to the crystallization ofthese films and good preliminaryresults were demonstrated during thiswork. Other techniques developedduring this work include the high reso-lution electron beam induced current(EBIC) imaging of polycrystalline sili-con cells. Because the grain size insuch material may be only of the orderof a micron, much higher resolutionthan normally obtained with the EBICtechnique is required.


� S16

Thin-Film Solar Cells

Project Leader:

Dr Jurek Kurianski (to 8/93)

Dr Alistair Sproul (to 11/98)

Dr Armin Aberle (from 11/98)

Other Contributors:

Dr Pietro Altermatt, A/Professor Paul

Basore, Robert Bardos, Dr Matthew

Boreland, Dr Patrick Campbell,

Dr Benjamin Chan, Professor Martin Green,

Dr Mark Gross, Dr Stephen Healy,

Dr Mark Keevers, Daniel Krcho, Oliver

Nast, Dirk-Holger Neuhaus, Kazuo Omaki,

Dr Tom Puzzer, Dr Stephen Robinson,

Dr Michael Taouk, Professor Stuart

Wenham, Dr Guang Fu Zhang

The thin-film solar cell work conduct-ed at the Centre can be divided intothree phases. The first phase predatedthe formation of Pacific Solar in early1995, and was involved with the inves-tigation of techniques for the deposi-tion of silicon on glass and the devel-opment of appropriate cell structuresto allow high performance from suchdeposited material. With the forma-tion of Pacific Solar, many of the staffinvolved with this work were secondedto the new company to help develop asequence suitable for pilot production.The key role for the Centre thenbecame one of supporting this com-mercialisation effort by undertakingdetailed characterisation of the materi-al and devices being fabricated byPacific Solar. In the third and mostrecent phase, the Centre has re-established thin-film programs inde-

pendent of those being conducted atPacific Solar.

Work in the first phase of activitiesattempted to prepare high quality poly-crystalline films of silicon on glass. Atthis stage, it was believed that extreme-ly good quality material would berequired to reach reasonable levels ofcell performance and the emphasiswas on techniques consistent withobtaining such good quality. Con-siderable progress was made with solu-tion growth of silicon films onto glassand with the use of metal-inducedcrystallisation of silicon films, duringthis period.

There was a change in emphasis in thiswork with the invention of the multi-layer cell of Figure S12. By arrangingto have multiple junctions connectedin parallel dispersed throughout thecell volume, it was possible to makethe whole volume photovoltaicallyactive regardless of the quality of sili-con material. This opened up a farwider range of material depositionpossibilities, since the originally anticipated high quality was no longeressential.

Proof of concept work conducted bythe Centre established the high effi-ciency potential of this approach withworld record efficiency of 17.6%established for a thin multilayer cellgrown on a good crystallographicquality, but electronically inert, siliconwafer template.

In 1995, Pacific Solar came into oper-ation and began its own programbased on the prior work conductedwithin the Centre. Key researchersfrom the Centre were seconded toassist in this program. Steps were takento allow the company to develop thistechnology with an appropriate levelof commercial confidentiality. Accord-ingly, the Centre program entered thesecond phase where most of theCentre's work dealt with characterizingmaterials and devices fabricated byPacific Solar. Notable achievementsduring this period included the devel-opment of optical techniques formeasuring the absorption properties

FIGURE S12: MULTILAYER

SOLAR CELL.

FIGURE S13: ABSORPTION CO-EFFICIENT FOR SPUTTERED AND ANNEALED

SILICON FILMS, SHOWING DEFECT ABSORPTION ABOVE AND BELOW THE

BANDGAP. THE C-SI DATA IS TAKEN FROM THE WORK OF GREEN.

FIGURE S15: SEM PICTURE OF:

(A) THE A-SI/AL/GLASS STRUC-

TURE BEFORE ANNEALING AND

(B) THE AL(+ SI)/POLY-SI/GLASS

STRUCTURE RESULTING FROM A

30 MIN. ANNEAL AT 500�C.

S14: ELECTRON BEAM INDUCED

CURRENT (EBIC) IMAGE OF A

5 LAYER MULTIJUNCTION CELL

GROWN ON A POLYCRYSTALLINE

SILICON SUBSTRATE.

(IMAGE BY DR TOM PUZZER).

FIGURE S16: HIGH-RESOLUTION

EBIC IMAGE OF INTERSECTING

GRAIN BOUNDARIES IN A LARGE-

GRAINED POLYCRYSTALLINE

SILICON SOLAR CELL.

The approach taken is to use low ener-gy electron beams (typically 2-5 keV)instead of the more typical 20-30 keV.Lower energy means the excitationvolume within the silicon is smallerand can have a diameter of less than 1micron. Figure S16 shows a high reso-lution EBIC image of intersectinggrain boundaries in a large grain poly-crystalline silicon film showing the

SUPPORTING FUNDAMENTAL WORK

S19 �

of some of the activity under

the new Special Research Centre

for Third Generation Photo-

voltaics. It also led to new infor-

mation on the properties of

rare-earth metals in silicon and

the mechanisms for charge

interchange between rare earth

atoms and the silicon crystal

in collaborative work with FOM

Institute for Atomic and

Molecular Physics of the

Netherlands. Recombination in

solar cell depletion regions was

also extensively studied due to

its relevance to multilayer cell

design. The increased under-

standing gained led to new

design concepts allowing min-

imisation of this recombination

effect. Other work involved

development of a range of tech-

niques for the electrical and

optical characterisation of solar

cells and the constituent materi-

als. For example, FTIR allowed

characterisation of impurities,

free carrier behaviour and the

properties of thin and layered

samples. Figure S18 shows

an infrared photoconductivity

spectrum of a lightly boron

doped floatzone silicon wafer at

a temperature of 20K. The

sharp lines represent electronic

bination coefficients at high

excitation levels. The role of

excitons upon room tempera-

ture performance of silicon

solar cells was also explored

leading to new insights into

minority carrier behaviour in

solar cells and other semicon-

ductor devices.

transitions while the broad max-

imum is due to photo-ionization

of impurities in the material.

Other work involved in investi-

gation of second order effects

of significance in device design.

This included the effect of dop-

ing upon the density of states in

silicon material and the behav-

iour of the silicon Auger recom-


� S18

Project Leader:

Dr Alistair Sproul (to 11/98)

Dr Armin Aberle (from 11/98)

Other Contributors:

Dr Pietro Altermatt

Donald Clugston

Dr Richard Corkish

Dr Sean Edmiston

Roland Einhaus

Frank Geelhaar


Dr Om Kumar Harsh

Dr Gernot Heiser


Yidan Huang

Dr Mark Keevers

Daniel Krcho

Marco Lammer

Axel Neisser

Holger Neuhaus

Andreas Stephens

Dr David Thorp


A range of supporting funda-

mental work both assisted the

previous device research pro-

grams and also benefited from

the availability of devices and

processing techniques of unique

capabilities. In the latter area,

significant results were achieved

in defining new values for vari-

ous silicon material parameters

of relevance to photovoltaics

and the broader microelectron-

ics area. This work has been

made possible by the high quali-

ty of device processing available

to the Centre through its device

research programs. Early in the

Centre's life, specially construct-

ed diodes were used to derive

new experimental values for sili-

con's intrinsic carrier concentra-

tion. Similar capabilities allowed

new values to be extracted for

silicon's minority carrier mobili-

ty as a function of doping level

in the substrate. Similarly, high

performance cells provided an

ideal test vehicle for measuring

the absorption coefficient of sil-

icon to unprecedently small val-

ues (Figure S17). Band absorp-

tion processes at photon ener-

gies well below the bandgap

were detected with the energy

up to 4 phonons contributing to

the absorption processes.

Another large strand of activity

has involved the numerical mod-

elling of silicon solar cells. The

Centre has been fortunate in

having access to some of the

most advanced silicon device

simulators internationally and

has, in fact, contributed to the

further development of these

simulation packages. For one

dimensional simulation, the

Centre has contributed to the

recent development of the

international standard simulator,

PC1D, and acted as distributor

of this improved software pack-

age. For 2D and 3D simulations,

the Centre has worked with

ETH, Zurich on the develop-

ment of Dessis. This package

was used by the Centre for some

of the first ever 3D solar cell

simulations, which were of great

benefit in refining the design of

experimental devices.

The impurity photovoltaic effect

was extensively studied during

the grant period and led to new

insights into important features

of such multiple photon

absorption schemes. The inter-

est created by this work has

been at least partly responsible

for interest in the multi-band

structures that form the focus

Supporting Fundamental WorkSupporting Fundamental Work

FIGURE S17: ABSORPTION COEFFICIENT OF SILICON.

FIGURE S18: INFRARED PHOTOCONDUCTIVITY SPECTRUM OF A BORON

DOPED (100 �CM) FLOAT-ZONE SILICON WAFER AT APPROXIMATELY 20K.

S Y S T E M S R E S E A R C H

E D U C A T I O N , T R A I N I N G

S21 �


� S20

Project Leader:

A/Professor Hugh Outhred

Other Contributors:

Stillisn Atanassov, Fabio Barone,

Dr Trevor Blackburn, Dr Kevan Daly,

Mark Ellis, Dave Gilbert, Mark Hancock,

Greg Harbidge, Dr John Kaye, Erik Keller,

George Kinnell, Robert Largent,

Iain MacGill, Dr Adelle Milne,

Professor Ian Morrison, Dorothy Remmer,

David Roche, Professor Bent Sorensen,

Ted Spooner, Dr Qi Su, Dr Dean Travers,

Dr Muriel Watt

One of the Centre's original aims

was to stimulate a range of co-ordi-

nated photovoltaic systems activities

at the University using funding

largely from other sources. The

Centre has been remarkably success-

ful in achieving these aims. Com-

bined with the fortunate timing of

the Centre's inception, the Centre

has had an impact in the systems

area out of all proportion of the

seeding funds expended to stimulate

these activities.

Success of the Centre in this area was

greatly enhanced by major grants

early in the Centre's history from

local power companies, Pacific Power

and EnergyAustralia. Both compa-

nies have gone on to a more substan-

tial involvement in photovoltaics,

using the experience gained through

funding Centre activities as the base

for these further activities. As men-

tioned earlier, Pacific Power is now

the major shareholder in Pacific

Solar, a company formed specifically

to commercialise the Centre's thin

film polycrystalline silicon-on-glass

technology, with a focus towards

marketing residential photovoltaic

systems. EnergyAustralia was one of

the first power companies to intro-

duce “green energy” schemes into

Australia through its Pure Energy

scheme. EnergyAustralia has com-

missioned the installation of the

largest photovoltaic system in the

southern hemisphere at Singleton as

a result of this program. It is unlikely

that either company would have been

as heavily involved in photovoltaics

without their prior interaction with

the Centre.

The Centre was also heavily

involved with another major pho-

tovoltaics initiative. This was the

use of photovoltaics for the

Athletes' Village for the Sydney

2000 Olympics. Centre Director,

Martin Green, participated in

early meetings formulating fea-

tures of the ultimately successful

bid tender by Mirvac/Lendlease.

Ted Spooner has been actively

involved in the development of

guidelines for the development of

inverters for use in such grid-con-

nected residential systems as well

as being heavily involved in test-

ing of the inverters used in the

installation, to ensure they comply

with these guidelines. The success

of this initiative, in turn, has

undoubtedly contributed to the

Government's announcement of

a $31 million scheme to subsidise

the more widespread use of resi-

dential photovoltaic systems in

Australia.

The main test bed for system testing

is at the University's Solar Research

Facility at Little Bay. Here, there are

two 2 kW arrays, one using

monocrystalline silicon and the sec-

ond using multicrystalline silicon as

well as a 1 kW triple junction amor-

phous silicon cell array (see Facilities

section of this publication). These

arrays can be configured to be grid-

connected or to be used for stand-

alone system experiments.

Researchers affiliated with the

Centre have contributed to areas

across the breadth of issues relevant

to photovoltaic applications. Areas

of special interest have been elec-

tricity industry restructuring and

regulation, institutional and environ-

mental issues relating to the use of

photovoltaics, power system interac-

tion and economics, system hard-

ware and performance monitoring,

remote area power supplies, residen-

tial photovoltaics and the develop-

ment of standards.

Systems ResearchSystems Research

FIGURE S19: PART OF THE OLYMPIC ATHLETES' VILLAGE

SHOWING ROOF-MOUNTED PHOTOVOLTAICS.

Sydney (Figure S21). Data from the

Centre's Little Bay installation is

accessible via the internet in a “virtu-

al power station” concept for schools

without their own system.

During the grant period, the

Centre also supported technology

transfer through Unisearch Ltd.,

the commercial arm of the

University. As well as the activi-

ties with Pacific Solar previously

mentioned, the Centre provided

support to licensees of wafer-

based technology BP and Solarex,

now BP Solarex, as well as

to Telefunken Systeme Technik

(now ASE GmbH), Central

Electronics Ltd. (India), Euro-

solare (Italy), and Samsung

(Korea). This often involved

training on the Centre's pilot line

during extended visits by a team

from the licensee's staff as well as

visits to the licensee's site by

Centre staff.

technical report for the 1996 World

Solar Challenge commissioned from

the Centre and, in 1999, by

“Crystalline Silicon Solar Cells:

Advanced Surface Passivation and

Analysis” by Dr Armin Aberle.

A number of international short

courses were delivered during the

grant period, such as the three-week

intensive course in Applied Photo-

voltaics delivered to Indonesian

BPPT staff during 1998. For local

practitioners, the Centre was also

involved with the development and

presentation of training courses for

photovoltaic systems for the Solar

Energy Industries. The Centre also

has pioneered leading-edge technolo-

gy for course presentation, such as

the interned-based “Applied Photo-

voltaics” course run during 1998 and

1999. Course material was supplied

via a Centre supported CD-ROM,

with tutoring over the internet for

the largely international participants

in this course.

Apart from lectures to high school

and gifted students and hosting

Centre visits for such students, a

1 kilowatt array was installed on the

roof of Fort Street High School in

Academic Contributors:

Dr Armin Aberle,

Dr Jeff Cotter,

Professor Martin Green,

Michelle Guelden,

Dr Christiana Honsberg,

Dr John Kaye,

A/Professor Hugh Outhred,

Dr Rodica Ramer,

Professor Stuart Wenham,

Dr Muriel Watt

Business Manager:

David Jordan (to 8/97)

Mark Silver (from 8/97)

Other Contributors:

Dr Stuart Bowden, Dr Kerrie Davies,

David Roche, Dr Ted Szpitalak,

Michael Taouk, Michael Willison,

Dr Jianhua Zhao

The major education activities of the

Centre addressed postgraduate

education, although these broadened

out to address undergraduate and

high school students, and the wider

community.

Postgraduate education occurred via

thesis research supervision and

through the development and pres-

entation of formal postgraduate

courses. A total of 34 postgraduate

theses were completed during the

grant period, of which 22 were at the

doctoral level. A listing of these the-

ses for the 1991-1999 period can be

found in the publications list at the

rear of this report. A Master of

Engineering Science course strand

for students wishing to specialise in

photovoltaics was also developed.

The lecture notes for the correspon-

ding courses and parallel courses

offered to final year undergraduate

students were expanded out to form

the basis of three textbooks released

by the Centre as a trilogy in 1995

(Figure 20). These were joined in

1997 by the “Speed of Light”, the

FIGURE S20: CENTRE TEXTBOOK

TRILOGY RELEASED IN 1995.

Education,Training & Technology Transfer

FIGURE S21: FORT STREET

HIGH SCHOOL WITH 1 KW PV

SYSTEM VISIBLE ON ROOF.

Education,Training & Technology Transfer

E X T E R N A L C O N T A C T S

F I N A N C I A L S

S23 �


� S22

EEXXTTEERRNNAALL RREELLAATTIIOONNSS MMAANNAAGGEERR::

Michael Willison (to 3/94)

Michelle Guelden (from 3/94 to 3/96)

David Roche (from 3/96 to 10/98)

Robert Largent (from 10/98)

Design Assistance Div. Manager:

Robert Largent

Other Contributors:

Dr Christiana Honsberg,

David Jordan, plus many other staff

The Centre's external contacts were

wide and varied, ranging from links

to other local and international

research institutes to providing

advice on photovoltaic use to mem-

bers of the community previously

not familiar with this technology.

Good links were established with

other research groups in Australia

and overseas interested in photo-

voltaics, including most major labo-

ratories, with staff interchange

involved in several cases. Visitors to

the Centre for prolonged periods

included researchers from China,

Denmark, Germany, Japan, Ger-

many, Netherlands, Switzerland and

the USA. As well as students from

other Australian universities, the

Centre additionally attracted post-

graduate students from China,

Germany, Iran, Japan, New Zealand,

Nigeria, Philippines, Switzerland,

Thailand, the UK and the USA.

The Centre's External Relations

Section and the Design Assistance

Division provided the main routes for

formal contact with the wider com-

munity, apart from those involving

formal education, or training or trans-

fer of the Centre's device technology.

Major installations in which the

Design Assistance Division has played

a role include a 4 kilowatt hybrid

system installed by National Parks and

Wildlife on Montague Island (Figure

S22), off the New South Wales coast,

a 4 kW hybrid system at Green Cape

National Park on the New South

Wales far south coast, as well as many

smaller projects.

Some of these smaller projects have

involved assisting local artists, such

as Allan Giddy and Joyce

Hinterding, in incorporating photo-

voltaics into their art. Figure S23

shows Allan Giddy's Ice Heart sculp-

ture on Tamarama Beach, Sydney in

1999 using photovoltaics to cool a

block of ice at the apex of the

pyramid in the centre of the

photograph. Joyce Hinterding’s

Koronatron exhibited in Ober-

hausen, Germany between April

and October, 1996, was powered by

nearly a kilowatt of photovoltaics.

External ContactsExternal Contacts

FIGURE S22: MONTAGUE ISLAND: 4 KWP PV

ARRAY USED TO POWER ISLAND COMMUNITY.

FIGURE S23: ALLAN GIDDY’S

ICE HEART SCULPTURE ON

TAMARAMA BEACH, SYDNEY.

The total grant under the ARC

Special Research Centres Scheme

was $8,850,234 over the 1991-1999

timeframe, averaging approximately

$1 million/year in current dollars.

The original plan for the Centre was

to use this funding to provide infra-

structure for Centre operations, seed-

ing funds to bring projects to the

stage where they could attract exter-

nal funding, and complementary

funding to improve the viability and

scope of externally supported proj-

ects. In this plan, most of the funds

for Centre activities were to be from

additional external grants with the

ARC funds targeted to account for

less than 45% of Centre expenditure.

This target has been achieved, with

the Special Research Centres Grant,

representing only about 40% of

funds expended on Centre-related

activities. Apart from other ARC

schemes such as the Research

Fellowship and Large and Small

Grant Schemes, substantial external

funding has been received from

Pacific Solar, the former Energy

Research and Development

Corporation, Pacific Power, the

NSW Office of Energy, Sandia

National Laboratories, Energy

Australia, the Humboldt Foundation,

and other Australian government

departments (such as DITARD,

AIDAB). The University of New

South Wales was also a major con-

tributor in many ways, particularly

through its Major Equipment and

Infrastructure Grants.

Additionally, commercial activities

through Unisearch Ltd generated

substantial additional income such

as from licence fees, royalties, con-

sulting and the sale of high per-

formance solar cells for solar car

racing. Most of this income has

been invested in the Centre's tech-

nology transfer facilities in

Bay Street, Botany. These

facilities have generated income

from rent for the Centre and will

provide future support for Centre

related activities.

Figure S24 shows the breakdown of

the expenditure of ARC Special

Research Centre funds of $8,850,234

by expenditure category. The largest

single expenditure category has been

salaries that accounted for close to

40% of overall expenditure. A simi-

lar amount was spent on materials,

generally those required for provid-

ing operational and laboratory infra-

structure. Smaller amounts were

expended on equipment and travel.

Figure S25 shows the breakdown by

project area of ARC Special

Research Centre funds. The ARC

funds have been used primarily to

provide infrastructure by supporting

the operation, maintenance and

development of Centre laboratories

and facilities with a smaller amount

used as seeding funds for system

and device research activities.

FinancialsFinancials

FIGURE S24: BREAKDOWN OF EXPENDITURE OF

ARC SPECIAL RESEARCH CENTRE FUNDS BY CATEGORY.

FIGURE S25: BREAKDOWN OF

EXPENDITURE OF ARC SPECIAL

RESEARCH CENTRE FUNDS BY

PROJECT AREA.

P U B L I C A T I O N S

S25 �

Sun, J. and Zhao, J., “Science and

Technology - Advancing into New

Millennium”, People's Education

Press, China (in English and

Chinese), September, 1999.

Refereed Journals(1999)Aberle, A.G., “Overview on SiN

Surface Passivation of Crystalline

Silicon Solar Cells”, Solar Energy

Materials and Solar Cells (in press).

Altermatt, P.P., Sinton, R.A. and

Heiser, G., “Improvements in

Numerical Modelling of Highly

Injected Crystalline Silicon Solar

Cells”, Solar Energy Materials and

Solar Cells, (in press).

Bremner, S., Corkish, R. and

Honsberg, C.B., “Detailed Balance

Limits with Quasi-Fermi Level

Variations”, IEEE Transactions on

Electron Devices, Vol. 46, No.10,

pp. 1932 - 1939, 1999.

Corkish, Richard, Altermatt, Pietro

P. and Heiser, Gernot, “Simulation

of Electron-Beam-Induced Cur-

rent Near a Grain Boundary in a

Silicon Solar Cell”, Solar Energy

Materials and Solar Cells, (in press).

Cotter, J.E., Hall, R.B., Mauk, M.G.

and Barnett, A.M., “Light Trapping

in Silicon-film( Solar Cells with Rear

Pigmented Dielectric Reflectors”,

Progress in Photovoltaics, Vol. 7,

pp. 261-274, 1999.

Cotter, J.E. and Freedman, S., “Speed

of Light - Virtual Solar Car Racing”,

Solar Progress, Vol. 20, p. 29, 1999.

Green, M.A., Emery, K., Bücher,

K., King, D.L. and Igari, S., “Solar

Cell Efficiency Tables (Version

13)”, Progress in Photovoltaics,

Vol. 7, pp. 31-38, 1999.

Connected Photovoltaic Systems”,

MEngSc thesis, University of New

South Wales, 1997.

Richards, B.S., “Optical Charac-

terisation of Sputtered Silicon

Thin Films for Photovoltaic

Applications”, MEngSc thesis,

University of New South Wales,

February, 1998.

S. Ghaemi, “Deposition of Poly-

Crystalline Silicon on Non-

Silicon Substrates using Multi

Component Metal Solutions of

Silicon by Liquid Phase

Epitaxy”, PhD thesis, University

of New South Wales, 1999.

Boreland, M., “Laser Crystal-

lisation of Silicon for Photovoltaic

Applications using Copper Vapour

Lasers”, PhD thesis, University of

New South Wales, 1999.

Books BookChapters (1999)Aberle, A.G., “Crystalline Silicon

Solar Cells - Advanced Surface

Passivation and Analysis” (Centre for

Photovoltaic Engineering, University

of New South Wales, Sydney NSW

2052, Australia, 340 pages, Sept.

1999, (ISBN 0 7334 0645 9).

Aberle, A.G., “PECVD silicon

nitride: Review of the fundamental

properties and prospects for applica-

tion in the photovoltaics industry”, in

Recent Research Developments in

Vacuum Science and Technology

(Transworld Research Network,

Trivandrum, in press).

Green, M. A., “Crystalline Silicon

Solar Cells”, in Imperial College

Series on Photoconversion, M.D.

Archer (Ed.) (Imperial College

Press, London, (in press).


� S24

1991-1999 ThesesHancock, M., “Remote Area

Power Supply Controller”, BE

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New South Wales, November,

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Milne, A., “The Passivated Emitter

and Rear Solar Cell”, PhD thesis,


June, 1991.

Travers, D., “Storage in Remote

Area Power Supplies: Technical

Characterisation, Optimal Control

and System Design”, BE (Honours)

thesis, University of New South

Wales, November, 1991.

Healey, S.A., “The Low

Temperature Solution Growth of

Thin-Film Silicon and Silicon ger-

manium Alloys and their use for

Photovoltaic Applications”, PhD


Wales, January, 1992.

Sarochawikasit, R., “Remote Area

Power Supply by a Hybrid

PV/Battery/Diesel Generation

System”, MSc thesis, University of

New South Wales, January, 1992.

Shi, Z., “Solution Growth of

Polycrystalline Silicon Thin Films

on Glass Substrates for Low-Cost

Photovoltaic Cell Application”,

PhD thesis, University of New

South Wales, February, 1992.

Sproul, A.B., “Silicon Intrinsic

Carrier Concentration and

Minority Carrier Mobility”, PhD


Wales, June, 1992.

Wang, A., “High Efficiency PERC

and PERL Silicon Solar Cells”,


South Wales, October, 1992.

Chan, B.O., “Defects in Silicon

Solar Cell Materials”, PhD thesis,


March, 1993.

Cho, V.H., “Design and

Performance of Solar Cell

Illuminated I-V Tester”, MEngSc


Wales, 1993.

Corkish, R., “Limits to the

Efficiency of Silicon Solar Cells”,


South Wales, 1993.

Debuf, D., “Analysis of Multi-

Exponential Signals Applied to

Photoconductance Decay”,

MengSc thesis, University of New

South Wales, July, 1993.

Krimwongrut, P., “Disturbances in

Low Voltage Systems”, MEngSc


Wales, 1993.

Roche, D., “Solar Mismatch

in Photovoltaic Arrays”, BE

(Honours) thesis, University of

New South Wales, 1993.

Altermatt, P.P., “Two Dimensional

Numerical Modeling of High

Efficiency Silicon Solar Cells”,

Diplomarbeit, Universitat

Konstanz, July, 1994.

Dai, X., “High Efficiency N-Type

Silicon Solar Cells”, PhD thesis,


1994.

Ebong, A., “Double Sided Buried

Contact Silicon Solar Cells”, PhD


Wales, November, 1994.

Zhang, W., “Liquid Phase

Epitaxial Growth of Silicon

Thin Films for Solar Cell

Application”, ME thesis, University

of New South Wales, 1994.

Robinson, S.J., “Non-Ideal”

Electrical Characteristics of

Crystalline Silicon Solar Cells”,


South Wales, January, 1995.

Davies, K., “Hollow Cathode

Discharges for Dry Processing of

Microstructures”, PhD thesis,


March, 1995.

Hancock, M., “A New Method for

Optimising the Operation of

Remote Area Power Supply

(RAPS) Systems”, ME thesis,


August, 1995.

Einhaus, R., “Design of a New

Characterisation Instrument for

Bifacial Solar Cells”, Diplomarbeit

im Fachbereich Fotoingenieur-

wesen and der Fachhochschule

Koln (Germany) and University of

New South Wales, October, 1995.

Jurgens, J., “Examination of Loss

Mechanisms in the Rear Floating

Junction of PERF Solar Cells”,

Technische Universitat Berlin

(Germany) and University of New

South Wales, November, 1995.

Zhang, F.Z., “Buried Contact

Silicon Concentrator Solar Cells”,


South Wales, December, 1995.

Stephens, A., “Application of

Photoconductance Decay Mea-

surements to Silicon Solar Cell

Characterisation”, PhD thesis,


May, 1996.

Thorp, D., “Absorption Enhance-

ment in Thin-Film Polycrystalline

PublicationsPublicationsSilicon Photovoltaic Modules”,


South Wales, July, 1996.

Ghozati, S., “High Efficiency

Double Sided Buried Contact Bi-

Facial Silicon Solar Cells”, PhD


Wales, August, 1996.

Bowden, S., “A High Efficiency

Photovoltaic Roof Tile”, PhD the-

sis, University of New South

Wales, September, 1996.

Keevers, M.J., “Improved Perfor-

mance of Silicon Solar Cells by the

Impurity Photovoltaic Effect”,



Zheng, G.F., “High Efficiency

Thin-Film Silicon Solar Cells”,



Edmiston, S.A., “Modelling of

Thin Film Crystalline and

Polycrystalline Silicon Solar Cells”,


South Wales, February, 1997.

Harsh, O.K., “Involvement of

Free and Bound Excitons and

Exciton Molecules in Transport

and Recombination in Silicon Solar

Cells and Related Devices”, MSc


Wales, April, 1997.

Altermatt, P.P., “The Charac-

terisation and Optimisation of

High-Efficiency Silicon Solar Cells

by Means of Numerical Sim-

ulations”, PhD thesis, University

of Konstanz and University of

New South Wales, November,

1997.

Johnson, A.J., “Life Cycle

Assessment of Inverters for Grid-


S27 �

Wenham, S.R., Koschier, L.M.,

Nast, O. and Honsberg, C.B.,

“Thyristor Photovoltaic Devices

formed by Epitaxial Growth”,

IEEE Trans. on Electron Devices,

Vol. 46, pp. 2005-2012, 1999.

Zhao, J., Wang, A., Campbell, P.

and Green, M.A., “22.7% Efficient

Silicon Photovoltaic Modules with

Textured Front Surface”, IEEE

Trans. on Electron Devices, Vol.

46, pp. 1495-1497, 1999.

Zhao, J., Campbell, P. and Green,

M.A., “19.8% Efficient Honey-

comb Multicrystalline Silicon Solar

Cell with Improved Light

Trapping”, IEEE Trans. on

Electron Devices, Vol. 46, pp.

1978-1983, 1999.

Zhao, J., Wang, A. and Green,

M.A., “24.5% Efficiency Silicon

PERT Cells on MCZ Substrates

and 24.7% Efficiency PERL Cells

on FZ Substrates”, Progress in

Photovoltaics, Vol. 7, pp. 471-474,

October, 1999.

Zhao, J., Wang, A., Zhang,

G. and Altermatt, P., “MOS Gate

Passivation to Peripheral Areas of

High Efficiency Silicon Solar Cells,

and Other Methods for Edge

Passivation of Silicon Cells”,

Progress in Photovoltaics, (in press).

Zhao, J., Wang, A. and Green, M.

A.,”24.5% Efficiency PERT Silicon

Solar Cells on MCZ substrates and

Cell Performance on Other SEH

CZ and FZ Substrates”, Solar

Energy Materials and Solar Cells,

(in press).

Zhao, J., Wang, A. and Green, M.

A., “Performance Degradation in

CZ(B) Cells and Improved

Stability High Efficiency PERT

and PERL Silicon Cells on a

Campbell, P. and Green, M.A.,

“High Performance Light Trapping

Textures for Monocrystalline

Silicon Solar Cells”, Tech. Digest,

11th International Photovoltaic

Science and Engineering Con-

ference, Sapporo, September, 1999,

pp. 561-562.

Campbell, P., Keevers, M. and

Vogl, B., “Characterisation of

Light Trapping in Silicon Films by

Spectral Photoconductance Mea-

surements”, Tech. Digest, 11th


and Engineering Conference,

Sapporo, September, 1999, p. 333.

Corkish, R. and Honsberg, C.B.,

“Simulation of GaAs/InGaAs

Quantum Well Solar Cells”, Solar 99,

Geelong, December 1999 (Aus-

tralian and New Zealand Solar

Energy Society, 1999).

Corkish, R., Altermatt, P.P. and

Heiser, G., “Simulation of electron-

beam-induced current near a grain

boundary in a silicon solar cell”,

Technical Digest, 11th International

Photovoltaic Science and Engin-

eering Conference (PVSEC-11),

Sapporo, Japan, p. 289 (Sept. 1999).

Corkish, R., “Numerical Modelling

of Quantum-Well Solar Cells - A

Promising Means of Sustainable

Energy Production”, Morrow

Lindbergh, C.A. and A. Grant

progress report, May, 1999.

Corkish, R., “Numerical Modelling

of Quantum-Well Solar Cells - A

Promising Means of Sustainable

Energy Production”, Morrow

Lindbergh, C.A. and A. Grant final

report, August, 1999.

Green, M.A., “Recent Developments

in Photovoltaics”, Proceedings,

Symposium on New and Alternative

Variety of SEH MCZ(B), FZ(B)

and CZ(Ga) Substrates”, Progress

in Photovoltaics, (in press).

Conference Papersand Reports (1999)Aberle, A.G., and Wenham, S.R.,

“Overview on the High-Efficiency

Solar Cell Research Activities at the

University of New South Wales”,

Symposium Proceedings, Research

Collaboration Symposium, 1st

Australian Technology Week in

Taiwan (Taipei, Taiwan, April 1999,

in press).

Aberle, A.G., “Overview on SiN

Surface Passivation of Crystalline

Silicon Solar Cells”, Technical Digest,

11th International Photovoltaic Sci-

ence and Engineering Conference,

Sapporo, Japan, Sep. 1999,

pp. 569-572.

Altermatt, P.A., Schenk, A., Heiser,

G. and Green, M.A., “The Influence

of a New Band Gap Narrowing

Model on Measurements of the

Intrinsic Carrier Density in

Crystalline Silicon”, Tech. Digest,



ference, Sapporo, September, 1999,

pp. 719-720.

Altermatt, P.P., Sinton, R.A. and

Heiser, G., “Improvements in

Numerical Modelling of Highly

Injected Crystalline Silicon Solar

Cells”, Tech. Digest, 11th Inter-

national Photovoltaic Science and

Engineering Conference, Sapporo,

September, 1999, p. 293.

Bremner, S.P. and Honsberg, C.B.,

“Modelling a Quantum Well in the

Intrinsic Region of a P-I-N Solar

Cell”, Proc. Australian and New

Zealand Solar Energy Conference,

Geelong, December, 1999.


� S26

Green, M.A. “Two New Efficient

Crystalline Silicon Light Trapping

Textures”, Progress in Photo-

voltaics, Vol. 7, pp. 317-320, July,

1999.

Green, M.A., Emery, K., Bücher,


Cell Efficiency Tables (Version

14)”, Progress in Photovoltaics,

Vol. 7, pp. 321-326, July, 1999.

Green, M.A., “Limiting Efficiency

of Bulk and Thin-film Silicon

Solar Cells in the Presence of

Surface Recombination”, Progress

in Photovoltaics, Vol. 7, pp. 327-

330, July, 1999.

Green, M.A., Zhao, J., Wang, A.

and Wenham, S.R., “Very High

Efficiency Silicon Solar Cells -

Science and Technology”, IEEE

Trans. on Electron Devices, (invit-

ed), Vol. 46, pp. 1940-1948,

October, 1999.

Green, M. A., Zhao, J., Wang, A.

and Wenham, S.R. , “Progress and

Outlook for High Efficiency

Crystalline Silicon Solar Cells”, Sol.

En. Matls. Solar Cells, (in press).

Green, M. A., “Silicon Solar Cells:

At the Crossroads”, Special Issue,


Green, M.A., “The Future of

Crystalline Silicon Solar Cells”,

Progress in Photovoltaics, Special

Millennium Issue, (in press).

Green, M.A., Emery, K., Büücher,


Cell Efficiency Tables (Version 15)”,


Green, M. A., “Photovoltaics:

Technology Overview”, Energy

Policy, (in press).

Honsberg, C.B., Cotter, J.E.,

Richards B.S., Pritchard, S.C.,

Wenham, S.R., “Design Strategies

for Commercial Solar Cells Using

the Buried Contact Technology”,

IEEE Transaction on Electron

Devices, Vol 46 no. 10, pp1984-

1992, 1999.

Koschier, L.M., Wenham, S.R. and

Green, M.A., “Modeling and

Optimization of Thin-Film Devices

with Si1-xGex Alloys”, IEEE Trans.

on Electron Devices, Vol. 46, pp.

2111-2115, October, 1999.

McIntosh, K.R. and Honsberg,

C.B., “A New Technique for

Characterizing Floating-Junction-

Passivated Solar Cells from Their

Dark IV Curves”, Progress in

Photovoltaics, Volume 7, pp. 363-

378, 1999.

Nagel, H., Berge, C. and Aberle,

A.G., “Generalized Analysis of

Quasi-Steady-State and Quasi-

Transient Measurements of Carrier

Lifetimes in Semiconductors”,

Journal of Applied Physics,, Vol.

86, pp. 6218-6221, 1999.

Nast, O., Brehme, S., Neuhaus, D.-H.

and Wenham, S.R., “Polycrystalline

Silicon Thin Films on Glass by

Aluminum-Induced Crystallisation”,

IEEE Trans. on Electron Devices,

Vol. 46, p. 2062, 1999.

Nast, O. and Hartmann, A. J.,

“Influence of Interface and AI

Structure on Layer Exchange dur-

ing Aluminum-Induced Crys-

tallisation of Amorphous Silicon”,

submitted to Journal of Applied

Physics.

Nast, O., Brehme, S., Pritchard,

S., Aberle, A. G., and Wenham, S.

R., “Aluminum-Induced Crystal-

lisation of Silicon on Glass for

Thin-Film Solar Cells”, submitted

to Solar Energy Materials and

Solar Cells.

Nast, O. and Wenham, S. R.,

“Elucidation of the Layer

Exchange Mechanism in the

Formation of Polycrystalline

Silicon by Aluminum-Induced

Crystallisation”, Journal of

Applied Physics, (in press).

Neuhaus, D.H., Altermatt, P.P. and

Aberle, A.G., “Determination of

the Density of States in Heavily

Doped Regions of Silicon Solar

Cells”, Solar Energy Materials and

Solar Cells, (in press).

Paretta, A., Sarno, A., Tortora, P.,

Yakubu, H., Maddalena, P., Zhao, J.

and Wang, A., “Angle-Dependent

Reflectance Measurements on

Photovoltaic Materials and Solar

Cells”, Optics Communications,

(in press).

Rohatgi, A., Doshi, P., Moschner, J.,

Lauinger, A., Aberle, A.G. and

Ruby, D.S., “Comprehensive Study

of Rapid, Low-Cost Silicon Surface

Passivation Technologies”, IEEE

Trans. Electr. Dev. (April 2000).

Schumacher, J.O., Altermatt, P.P.,

Heiser, G. and Aberle, A.G.,

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Simulation of Saturation Current

Densities of Phosphorus Doped

Silicon Emitters”, Solar Energy

Materials and Solar Cells, (in press).

Wenham, S.R., Honsberg, C.B.,

Cotter, J., Largent, R., Aberle, A.G.,

Spooner, T. and Green, M.A.,

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S29 �


Sapporo City, September, 1999,

pp. 525-526.

Wenham, S.R. and Aberle, A.G.,

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SEH MCZ, CZ (Ga), CZ (B) and

FZ Si Substrates”, Final Report,

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and Tokyo University of Agri-

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1999 (10pp.).


M.A., “High Efficiency PERL

Silicon Solar Cells on FZ, MCZ

and CZ Substrates”, Tech. Digest,



ference, Sapporo, September,

1999, pp. 557-558.


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Sapporo, September, 1999, p. 979.


M.A., “24.7% Efficient PERL

Silicon Solar Cells and other

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Module Research at the Uni-

versity of New South Wales”,

ISES Solar World Congress,

Jerusalem, Israel, July, 1999.

Zhao, J., Wang, A. and Green, M.A.,

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UNSW Experiments on SHE

MCZ, CZ (Ga), CZ (B) and FZ

Silicon Substrates”, Workshop on

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Lifetimes in CZ-Si Solar Cells -

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Sapporo, Japan, September, 1999.


M.A., “Recent Performance Im-

provement of High Efficiency

Silicon Solar Cells”, Proceedings of

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December, 1999.

Zhao, J., Wang, A. and Altermatt,

P.P., “A MOS Capacitor Surface

Passivation Structure for Peri-

pheral Regions of High Efficiency





1999, pp. 339-340.


� S28

Energy Technologies, Pacific Science

Congress, Sydney, July, 1999 pp. 3-10

(ISBN 0 7334 0584 3).

Green, M.A., “Photovoltaics:

Moving From the Outback to the

City”, Solar Progress, Vol. 20, pp. 3-

5, September, 1999.

Green, M.A., J. Zhao, A. Wang and

S.R. Wenham, “Progress and

Outlook for High Efficiency

Crystalline Silicon Solar Cells”, Tech.

Digest, 11th International Photo-

voltaic Science and Engineering

Conference, Sapporo City, Sept-

ember, 1999, pp. 21-24.

Green, M.A., “High Efficiency

Silicon Solar Cells”, B. Courtois, S.

Demidenko (Eds.), Proceedings,

SPIE International Society for

Optical Engineering, ISBN 0-8194-

3494-9, Gold Coast, 27-29 October,

1999, pp. 69-81.

Green, M.A., “Solar Cells and

Renewable Energy”, in Trends in

Materials Science and technology, F.

Bekber, N. Chien, J. Franse, T. Hien,

N. Hien and N. Thesy (Eds.), Hanoi

National University 1999 Publishing

House, ISBN 90-5776-033-9, Pro-

ceedings of the Third International

Workshop on Materials Science,

Hanoi, Vietnam, November, 1999,

pp. 1-6.

Green, M.A. and Wenham, S.R.,

“Photovoltaics for the New Mill-

ennium”, Conf. Record, Australian

Institute of Energy National

Conference, Melbourne, November,

1999, pp. 44-52.

Green, M.A., “Photovoltaics -

Recent Developments”, ANZSES

Solar 99, Geelong, December, 1999.

Keevers, M.J., “Fabrication and

Characterisation of Parallel Multi-

junction Thin Film Silicon Solar

Cells”, Technical Digest, 11th



Sapporo, Japan, Sep. 1999, p. 933.

Nast, O., Brehmer, Pritchard, S.,

Puzzer, T., Aberle, A.G. and

Wenham, S.R., “Aluminum Induced

Crystallisation of Silicon on Glass

for Thin-Film Solar Cells”,



eering Conference, Sapporo, Japan,

Sep. 1999, pp. 727-728.

Neuhaus, D.H., Altermatt, P.P. and

Aberle, A.G., “Determination of the

Density of States in Heavily Doped

Regions of Silicon Solar Cells”,



eering Conference, Sapporo, Japan,

Sep. 1999, pp. 645-646.

Outhred, H. and Watt, M.,

“Prospects for Renewable Energy

in the Restructured Australian

Electricity Industry”, World Re-

newable Energy Congress, 10-13

February 1999, Perth, WA.

Saitoh, T., Wang, X., Hashigami,

H., Abe, T., Igarashi, T., Glunz, S.,

Wettling, W., Ebong, A., Damiani,

B.M., Rohatgi, A., Yamasaki, I.,

Nunoi, T., Sawai, H., Ohtuka, H.,

Yazawa, Y., Warbisako, T. Zhao, J.

and Green, M.A., M.A., “Light

Degradation and Control of Low-

Resistivity CZ-Si Solar Cells - An

International Joint Research”,

Tech. Digest, 11th International


eering Conference, Sapporo,

September, 1999, pp. 553-556.

Schumacher, J.J., Altermatt, P.P.,

Heiser, G., and Aberle, A.G.,

“Application of a New Bandgap

Narrowing Model to the Numerical

Simulation of Saturation Current

Densities of Phosphorus Doped

Silicon Emitters”, Technical

Digest, 11th International

Photovoltaic Science and

Engineering Conference, Sapporo,

Japan, Sep. 1999, pp. 291-292.

Vogl, B., Slade, A.M., Pritchard, S.C.,

Gross, M. and Honsberg, C.B., “The

Use of Silicon Nitride in Buried

Contact Solar Cells”, Tech. Digest, 11th

International Photovoltaic Science and

Engineering Confernce, Sapporo,

Japan, September, 1999, pp. 585-586.

Watt, M. and Outhred, H.,

“Australian and International

Renewable Energy Policy Ini-

tiatives”, World Renewable Energy

Congress, 10-13 February, 1999,

Perth, WA.

Watt, M. and Outhred, H., “Imple-

menting the Renewable Energy

Target”, Outlook 99, ABARE

Conference, 17-18 March, 1999,

Canberra.

Watt, M. and Outhred, H., “Review

of Policy Options for the Australian

Renewable Energy Industry”, Solar

99, 37th ANZSES Conference,

Geelong, Vic, 1-3 Dec, 1999.

Wenham, S.R., Zhao, J., Dai, X.

and Green, M.A., “Surface

Passivation in High Efficiency





1999, pp. 577-578.

Wenham S.R., Honsberg, C.B.,

Cotter, J., Largent, R., Aberle, A.,

Spooner, T. and Green, M.A.,

“Opportunities Arising Through

Rapid Growth of the Photovoltaic

Industry”, Tech. Digest, 11th


Photovoltaics

Special Research Centre

1999 Activities

Photovoltaics


1999 Activities

PV3 �


Table of ContentsTable of Contents

T A B L E O F C O N T E N T S

Staff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PV4

Facilities and Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PV6

PPhhoottoovvoollttaaiiccss RReesseeaarrcchh LLaabboorraattoorryy .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV66

DDeevviiccee CChhaarraacctteerriizzaattiioonn AArreeaa .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV77

PPoowweerr EElleeccttrroonniiccss LLaabboorraattoorryy .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV77

LLiittttllee BBaayy FFaacciilliittyy .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV77

Research Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .PV8

HHiigghh EEffffiicciieennccyy CCeellll GGrroouupp .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV88

EEffffiicciieennccyy IImmpprroovveemmeenntt ooff PPEERRLL CCeellllss .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV88

BBuurriieedd CCoonnttaacctt RReesseeaarrcchh RReeppoorrtt .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV1122

TThhiinn-FFiillmm GGrroouupp .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV1155

TThheeoorryy GGrroouupp .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2200

RReenneewwaabbllee EEnneerrggyy PPoolliiccyy aanndd PPllaannnniinngg .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2255

DDeessiiggnn AAssssiissttaannccee DDiivviissiioonn .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2266

GGrroooovvee DDiiffffuussiioonn .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..PPVV2277

PV5 �


� PV4

Stuart Wenham, BE, BSc, PhD (UNSW),

FTS, SNEE (also Head, Centre for

Photovoltaic Engineering)

Business & Technology Manager

Mark D. Silver, BE (UNSW), GMQ

(AGSM)

DDeessiiggnn AAssssiissttaannccee DDiivviissiioonnMMaannaaggeerr// EExxtteerrnnaall RReellaattiioonnssMMaannaaggeerr

Robert Largent, AS (USA)

AAddmmiinniissttrraattiivvee OOffffiicceeMMaannaaggeerr

Lisa Cahill

CCeennttrree CClleerrkkss

Jenny Hansen

Julie Kwan

Jenny Noble, BA (Hons) (UNSW) (P/T)

Anna Votsis (P/T) (to 6/99)

PPrroojjeecctt aanndd SSeenniioorr PPrroojjeecctt SScciieennttiissttss

Ted D. Spooner, BE, ME (UNSW)

Aihua Wang, BE, PhD (UNSW)

RReesseeaarrcchh FFeelllloowwss aanndd RReesseeaarrcchh AAssssoocciiaatteess

Pietro P. Altermatt, Dipl.-Phys., PhD

(Konstanz)

Patrick Campbell, BSc, BE, PhD

(UNSW)

Richard Corkish, BE (RMIT), PhD

(UNSW)

Nils Harder, Dipl.-Phys. (Leipzig)

(since 6/99)

Mark J. Keevers, BSc, PhD (UNSW)

Daniel Krcho, RNDr (Bratislava)

Ramakant Kumar, PhD, (India)

(5/99 to 7/99)

Hamid R. Mehrvarz, PhD (UNSW)

(to 4/99)

Oliver Nast, Dipl.-Phys. (TU, Berlin)

(to 11/99)

Tom Puzzer, BSc, PhD (UNSW) (P/T)

VViissiittiinngg SSttuuddeennttss

Martin Boettcher (Germany) (to 12/99)

Christian Haase (Germany) (to 12/99)

Marco Lammer (Germany) (to 4/99)

Jurgen Schumacher (Germany) (to 6/99)

SSppeecciiaall PPrroojjeeccttss

Brian Grems (P/T) (to 6/99)

Justin Lucas, BA (Hons) (Syd), PhD

(UNSW), (P/T to 11/99)

StaffStaffDDiirreeccttoorrss

Director

Martin A. Green, BE, MEngSc (Qld.), PhD

(McMaster), FAA, FTS, FIEEE, FIEAust. (to

12/99)

Director (High Efficiency)

Jianhua Zhao, ME, PhD (UNSW), MIEEE

(from 1/00)

Director (Buried Contact)

Christiana B. Honsberg, BEE, MSc, PhD

(Delaware) (from 1/00)

Director (Thin Film)

Armin G. Aberle, BSc, MSc, PhD

(Freiburg), Dr Habil (Hannover) MIEEE,

MDPG (from 1/00)

Associate Director (Systems)

Hugh R. Outhred, BSc, BE, PhD (Syd.),

AMIEE, MIEEE, FIEAust.

AAffffiilliiaatteedd AAccaaddeemmiicc SSttaaffff

Jeffrey E. Cotter, BEE, MSc, PhD

(Delaware)

Gernot Heiser, BSc (Freiburg), MSc

(Brock), PhD (ETH Zurich), SMIEEE,

MACM

John Kaye, BE, MEngSc (Melb.), PhD

(Calif.), MIEEE

Muriel E. Watt, BSc (UNE), PhD

(Murdoch)

S T A F F

AIHUA WANG PREPARING WAFERS FOR EMITTER DIFFUSION.

MARTIN BRAUHART AND MARK

SILVER DISCUSS LABORATORY

REFURBISHMENT PLANS.

JENNY HANSEN, ASSISTANT

TO CENTRE DIRECTOR,

MARTIN GREEN

NNoonn-AAwwaarrdd PPrrooffeessssiioonnaallPPrraaccttiiccuumm SSttuuddeenntt

Manfred Fahr (Efflingen)

LLaabboorraattoorryy aanndd RReesseeaarrcchh SSttaaffff

Professional Officers and

Research Assistants:

Robert Bardos, BSc (Hons) (Melbourne)

Travis Basevi, BE (UNSW) (P/T)

Gordon Bates, BA Ind.Des. (UTS)

(on leave 3/99 to 3/00)

Martin Brauhart, BE (UNSW)

Mark Gross, BSc (Syd), PhD (Syd)

(to 9/99)

Bryce Richards, BSc (Wellington),

MEngSc (UNSW) (P/T)

Lawrence Soria, Assoc.Dip.Comp.Appl.

(Wollongong)

Brendon Vandenberg, BE (Elec)

(UNSW) (P/T)

Bernhard Vogl, BE (Regensburg) (P/T)

Zhu S. Yang, BSc (China)

Technical and Senior

Technical Officers

Tim Seary

Stephen Sleijpen (P/T)

Guang C. Zhang, BE, ME (China)

Laboratory Assistant:

Anja Aberle (Germany) (to 9/99)

HHiigghheerr DDeeggrreeee SSttuuddeennttss

Masters

David Fuertas Marróóón, BSc (Madrid)

Faruque Hossain, BSc, MSc (Dhaka)

Attachai Uerananantasum, BE (Thailand)

Bernhard Vogl, BE (Regensburg)

Johnny Wu, BE, BSc (Queensland)

Doctoral

Matt Boreland, BSc (UNSW) (to 8/99)

Stephen Bremner, BSc (UNSW)

Donald. Clugston, Bsc (Syd)

Didier Debuf, BE, ME (UNSW)

Susie Ghaemi, BE (UNSW) (to 8/99)

Linda Koschier, BE (UNSW)

Daniel Krcho, RNDr (Bratislava)

Keith McIntosh, BSc (Sydney)

Bradley O'Mara, BSc (Oregon IT)

Dirk- Holger Neuhaus, Dipl.-Phys.

(Hannover)

Stephen Pritchard, BA, BE (UNSW)

Dorothy P. Remmer, BAppSc (UBC)

Bryce Richards, BSc (Wellington),

MEngSc (UNSW)

Nicholas Shaw, BE (UNSW)

Alexander M. Slade, BSc (Monash)

Ting Zhang, Electronics Eng. (China)

MARK KEEVERS AND CHRISTIANA

HONSBERG MEASURING THE SPEC-

TRAL RESPONSE OF A SOLAR CELL.

LINDA KOSCHIER WITH A BATCH OF 4 INCH

FLOAT ZONE SILICON WAFERS.

PV7 �

NT based WWW server, one NT

Intranet Server, one Unix workstation

and one Unix computer and WWW

server, support the device laboratory,

the simulation and the Centre's

administrative activities. Another 15

PCs are dedicated for the computer

control of laboratory equipment.

The device laboratories, Character-

isation Area and adjacent facilities

operate 24 hours per day, 365 days per

year and are developed and main-

tained by the Laboratory Dev-

elopment and Operations Team. In

1999, the team, under the leadership

of Mark Silver, comprised 4 full time

and 5 part time employees, which

include electrical and industrial design

engineers and technicians, a physicist,

computer and network manager, and

administrative staff.

Construction work on a $0.5M refur-

bishment of key laboratory safety

infrastructure such as exhaust and

fume cupboards commenced in April

1999 and is due for completion

around May 2000.

Device Character-isation AreaSpace in the basement of the

Electrical Engineering Building was

made available to the Centre by the

University in 1995. The space contains

a reception area, seminar room,

library, offices for Centre staff inter-

acting with the public and industry,

including the Business & Technology

Manager and Design Assistance

Division Manager, computer worksta-

tions for the device modelling activi-

ties of the Centre, and the Device

Characterization Area.

The Device Characterization Area of

60m2 houses characterization equip-

ment including “Dark Star”, the

Centre's station for temperature con-

trolled dark current-voltage measure-

ments, the Centre's Fourier Transform

Infrared Spectroscopy system, Admit-

tance Spectroscopy system, Ellips-

ometer, photoconductance decay

equipment, infrared microscope and

equipment for spectral response and

related optical measurements.

Power ElectronicsLaboratoryThis m2 laboratory, within the School

of Electrical Engineering, is equipped

with a range of power supplies for

heavy current testing of DC-DC con-

verters and inverters including a 60 V

battery bank for remote area power

supply testing. A range of test equip-

ment is available including: high fre-

quency oscilloscopes; true RMS

meters up to 2 MHz response; current

probes up to 1000 A and all the usual

small metering equipment. The labo-

ratory also has a number of micro-

processor/microcontroller develop-

ment systems which include TMS

320C25, and 80C196 systems which

are particularly suited to power elec-

tronic applications. IBM-PC compati-

bles provide analysis software and

printed circuit design and plotting sys-

tems. The laboratory also has access

to programming facilities for a large

range of programmable logic arrays.

Little Bay Facility The Little Bay Solar Energy Research

Facility (approximately 10 minutes

drive from the main University cam-

pus) has been operating a grid con-

nected PV systems for over five years.

The initial installation at the facility

included a 3.8 kW array, battery sys-

tems and inverter connected to the

local grid. Currently, we have 3.8 kW

of BP and Solarex crystalline silicon

arrays and a further 1 kW of Canon

amorphous silicon array. These arrays

are patchable to a large range of


� PV6

atory was integrated into the

Photovoltaics Research Laboratory

complex.

The Photovoltaics Special Research

Centre also owns equipment within,

and has access to, the new Semi-

conductor Nanofabrication Facility

(SNF). This is a joint facility shared by

Physics and Electrical Engineering

and houses a microelectronics labora-

tory and a nanofabrication laboratory

for e-beam lithography.

Additional equipment is available on

the University campus, which is com-

monly used for cell work. Included in

this category are electron micro-

scopes, X-ray diffraction, surface

analysis and photoluminescence

equipment.

A computer network of 54 PCs, one

Novell Server, one NT Server, one

Facilities & Structures

PhotovoltaicsResearchLaboratoryThe Centre boasts the largest and

most sophisticated bulk silicon solar

cell research facility in Australia.

Laboratory space of 480 m2 is located

on three floors of the School of

Electrical Engineering Building and is

serviced with filtered and conditioned

air, appropriate cooling water, pro-

cessing gas, de-ionized water supply,

chemical fume cupboards and

exhausts. There is an additional area of

over 450m2 immediately adjacent to

the laboratories for the accommoda-

tion of staff, research students and

laboratory support facilities. Off site

areas totalling 200m2 are used for the

storage of chemicals and equipment

spare parts.

The laboratory is furnished with a

range of processing and characterisa-

tion equipment including 37 diffusion

furnaces, 6 vacuum evaporation depo-

sition systems, 3 laser scribing ma-

chines, ellipsometer, microwave carrier

lifetime system, rapid thermal anneal-

er, four point sheet resistivity probe,

quartz tube washer, silver, nickel and

copper plating units, infrared and visi-

ble wavelength microscopes, 3 wafer

mask aligners, spin on diffusion sys-

tem, automated photoresist dual track

coater, photoresist spinner, reactive

ion etcher, plasma enhanced chemical

vapour deposition system, glass sur-

face patterning press, TiO2 spray dep-

osition system, electron beam and

sputter deposition systems, and a labo-

ratory system control and data acquisi-

tion monitoring system. In August

1997 the Plasma Processing Labor-

Facilities & Structures

F A C I L I T I E S A N D S T R U C T U R E

FIGURE PV1: LOCATION MAP

FIGURE PV2: LAYOUT OF THE CENTRE WITHIN

THE ELECTRICAL ENGINEERING BUILDING

FIGURE PV3: LITTLE

BAY TRACKING ARRAYS.

series-parallel configurations and are

used for evaluating a variety of systems

under actual operating conditions.

All the systems are being monitored by

an extensive data acquisition system

which logs environmental and electrical

conditions of the systems under test.

A single axis tracking module test facil-

ity is also installed (see Figure PV3).

Each module is connected to an elec-

tronic load which enables a complete

current/voltage characteristic to be

obtained. A data acquisition computer

system controls the electronic loads

and logs environmental conditions,

module temperatures and electrical

characteristics of the modules under

test. The tracking system may be fixed

in orientation or tracked to investigate

module performance under both

conditions.

A range of other test equipment is

available including a Voltec PM3000A

harmonic analyser for investigating

quality of supply issues for both RAPS

and grid connected systems and a high

speed data acquisition system for inves-

tigating protection issues related to grid

connected systems.

The Centre's four major work areas are the Photovoltaics

Research Laboratory, the Device Characterization Area, the

Power Electronics Laboratory and the new Undergraduate

Teaching Laboratory. Systems work is also undertaken at

the Little Bay Research Facility.

PV9 �

cells in the module. This shingled

module encapsulation method com-

pletely eliminated the busbar shading

and busbar resistance loss. Two mod-

ules with such shingle encapsulation

method had demonstrated world

record module efficiency of 22.7%.

Using these PERL cells, Honda

Dream won the 1996 World Solar

Challenge with an astonishing aver-

age speed of 90 km/hr over the

3010 km race course.

Figure PV5 shows the history of

the efficiency evolution for silicon

solar cells. The Centre has made

major contributions to the silicon

solar cell efficiency evolution in the

last one and half decades. Table

PV1 lists the performance of the

most recent record breaking

PERL cell. One major improve-

ment came from the improved

short-circuit current densities of

these cells, helped by the reduced

cell current density. The fill fac-

tor of the cells was also signifi-

cantly improved without the

need for the previous double

metal plating technique.

RReeccoorrdd PPeerrffoorrmmaannccee PPEERRTTCCeellllss oonn MMCCZZ SSuubbssttrraatteess

Solar cells made on moderately to

heavily doped CZ(B) silicon

substrates normally have shown

a degradation problem and gen-

erally poorer cell performance.

To avoid such problems, high

efficiency cells have been fabri-

cated on MCZ(B) (boron

doped magnetically-confined

Czochralski grown), CZ(Ga),

and FZ(B) (boron doped float

zone) substrates. All these sub-

strates were supplied by Shin-

Etsu Handotai Co, Japan,

(SEH). Many of these SEH

materials have a reasonably high

resistivity from 1 �-cm to 5 �-

cm. To reduce the series resist-

ance of these cells, a PERT

(passivated emitter, rear totally-

diffused) cell structure was

developed, which is shown in

Figure PV6. In the experiments,

it was found that the PERT cells

metal shading loss of the picture

frame cell design. The recently

installed planetary motion vacu-

um coating system has con-

tributed to an improved unifor-

mity of the antireflection coating

layers, which also is thought to

have contributed to improved

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVIITTIIEESS

� PV8

efficiency, which is the highest ever

reported efficiency for a non-FZ

silicon solar cell.

EfficiencyImprovement ofPERL CellsFigure PV4 shows the high efficien-

cy PERL cell structure. In 1997, the

PERL cells were redesigned into a

picture frame metallisation layout to

more accurately define the illuminat-

ed area of the cell. This approach

also reduces the metallisation shad-

ing loss and metal resistance loss.

This new design quickly demonstrat-

ed improved AM1.5 efficiency for

silicon cells of 24.5% in 1998. This

efficiency record has been further

improved to 24.7% in 1999.

The picture frame cell design has the

cell centre illuminated area surround-

ed by a wide metal busbar. The fin-

gers perpendicular to the busbars are

designed to run into the centre of

this illuminated area. The efficiency is

based on the illuminated area. This

efficiency is known as the designated

illumination area efficiency. The pic-

ture frame busbar allows the cell illu-

minated area to be exactly defined to

eliminate any possible misalignment

of the aperture mask to cell periph-

eral regions during cell testing. This

picture frame design also has a

reduced metal finger length. This

allows these fingers to be made nar-

rower to reduce their shading loss,

while still allowing sufficient finger

metal to improve the cell fill factor.

The relevance of a designated illumi-

nation area efficiency was verified

when the Centre produced 20,000

large area PERL cells for the World

Solar Challenge solar car race in

Research ReportsResearch ReportsHigh EfficiencyCell Group

Senior Project Scientist:

Dr Jianhua Zhao (project leader)

University Staff:



Project Scientist:

Dr Aihua Wang

Research Fellow

Pietro Altermatt

Graduate Student:

David Fuertes Marrón (Masters)

Two of the major achievements of

the high efficiency cell group in

1999 were improving PERL cell

efficiencies and the fabrication of

high efficiency cells on non-FZ sil-

icon substrates.

One of the major objectives in

1999 for the high efficiency group

was to further improve the effi-

ciency of PERL (passivated emit-

ter, rear locally-diffused) cells. This

work has demonstrated a 24.7%

energy conversion efficiency for a

cell fabricated on a float-zone (FZ)

substrate, which is the highest ever

reported efficiency for a silicon

solar cell.

Another major objective was to

fabricate high efficiency cells on

non-FZ MCZ (magnetically-con-

fined Czochralski growth), CZ(B)

(boron doped Czochralski) and

CZ(Ga) (gallium doped

Czochralski) substrates. These

materials were supplied by Shin-

Etsu Handotai Co. (SEH), Japan

under a collaboration program.

One of these MCZ cells demon-

strated 24.5% energy conversion

R E S E A R C H R E P O R T S

FIGURE PV4: PASSIVATED EMITTER, REAR LOCALLY-DIFFUSED

(PERL) CELL WITH DOUBLE LAYER ANTIREFLECTION COATING.

FIGURE PV5: EFFICIENCY

EVOLUTION FOR SILICON

SOLAR CELLS.

TABLE PV1: THE PERFORMANCE OF THE RECORD PERL CELL WHICH

WAS TESTED AT SANDIA NATIONAL LABORATORIES, UNDER THE

STANDARD 100 MW/CM2 AM1.5 GLOBAL SPECTRUM AT 25�C.

Cell ID Voc Jsc FF Eff

(mV) (mA/cm2) (%) (%)

Wh20-2b 706 42.2 82.8 24.7

FIGURE PV6: PASSIVATED EMITTER, REAR

TOTALLY-DIFFUSED (PERT) CELL STRUCTURE.

TABLE PV2: THE PERFORMANCE OF THE PERT CELL ON A MCZ

SUBSTRATE, ALSO WAS TESTED AT SANDIA NATIONAL LABORATORIES,

UNDER THE STANDARD 100 MW/CM2 AM1.5 GLOBAL SPECTRUM AT 25�C.

Cell ID Voc Jsc FF Eff

(mV) (mA/cm2) (%) (%)

Ws9-4b 704 41.6 83.5 24.5

1996. Those cells had been designed

with a large busbar area, with the bus-

bar shaded under the next row of

PV11 �

MMOOSS PPeerriipphheerraall PPaassssiivvaattiioonn SSttrruuccttuurree

A MOS (Metal Oxide Semi-

conductor) capacitor structure,

as shown in Figure PV8, has

been investigated to passivate

the peripheral regions for high

efficiency silicon solar cells.

Figure PV8 shows the peripher-

al loss mechanisms in a high

efficiency silicon PERL solar

cell, namely: (a) light generated

carriers diffuse into the periph-

eral region; (b) oblique light

passes into the peripheral

region. The peripheral loss is

enhanced by the fact that the

surface recombination in the

shaded dark peripheral region of

the cell is considerably higher

than that in the illuminated

emitter area, as previous

research has concluded.

When a bias voltage, Vg, as

shown in Figure PV8, is applied

onto the peripheral MOS capac-

itor, it changes the silicon sur-

face status from inversion to

depletion and even to accumula-

tion. These changed surface

MMeeaassuurreemmeennttss ooff tthhee DDooppaanntt DDeennssiittyy

The doping level of the wafers

used for the fabrication of solar

cells is usually obtained from

resistivity measurements, using

an established resistivity/dopant

density relationship. This method

fails in new materials, where no

such relationship has been

established (as for magnetic

Czochralski silicon), or to mate-

rials where such a relationship is

not reproducible due to varia-

tions in grain size etc. Instead,

the doping level in the base may

be determined in fabricated cells

using capacitance-voltage (C-V)

measurements. However, most

theories used for the data evalu-

ation of C-V measurements are

based on the “high-low abrupt

junction” structure, whereas the

PERL cells have medium doped

emitters with a Gaussian dopant

profile. In order to clarify which

data evaluation procedure can

be applied to PERL cells, C-V

curves were simulated with the

software Dessis. The simulation

results were compared with our

measurements of PERL cells

whose dopant profiles are

known. An excellent agreement

was found between our numeri-

cal simulation and the experi-

ment. If analytical data evalua-

tion schemes are applied, the

theory of Hilibrand and Gold

yields the most precise results

among various commonly used

methods. This is so because

Hilibrand and Gold made no

restrictive assumptions on the

location of the edge of the

depletion region.

conditions considerably affect

the recombination rate at the sil-

icon surface, and hence modu-

late the cell performance. It was

found that for negative gate

bias, the short-circuit current

density decreases and the fill

factor increases, while the open-

circuit voltage generally stays

constant. This effect gives a

small overall increase in cell effi-

ciency for negative gate bias

voltage, since the change rate in

fill factor is slightly stronger

than that in short-circuit current

density.

This work concluded that a very

weak surface inversion channel

exits at the silicon surface under

the MOS capacitor. However, it

is believed that this channel can

be cut off by a special designed

boron diffused surface protec-

tion ring, and the efficiency

improvements might then be

then increased to 1% and 2%

relative for 4 cm² and 1 cm²

PERL cells respectively. These

areas will be further investigated

in the future.


� PV10

nation or a period of storage.

Hence, these substrates provide

a solution to the degradation

problem commonly occurring in

CZ(B) silicon substrates. The

work on this topic was awarded

a Best Paper Award at the



ference (PVSEC-11), Japan, in

September, 1999. A separate

Special Paper Award was also

received for collaborative work

in this area with the Fraunhofer

Institute for Solar Energy Sys-

tems and the Tokyo University

of Agriculture and Technology.

on SEH MCZ substrates have

given open-circuit voltages as

high as standard PERL cells on

Wacker FZ wafers. They also

gave very high cell efficiencies.

A total rear boron diffusion in

this PERT structure appears to

improve the surface passivation

quality of MCZ(B) and some

FZ(B) substrates. Hence, higher

open-circuit voltages were

observed for these PERT cells

than PERL cells for these SEH

MCZ wafers. It is also believed

that these MCZ(B) and other

SEH materials have consider-

ably improved material qualities

under SEH's current effort to

develop high quality substrates

particularly for photovoltaic

applications. This research has

widened our material selection

for high efficiency silicon cells.

Table PV2 shows the perform-

ance of the best PERT cell on a

SEH MCZ substrate. This cell

demonstrated an energy conver-

sion efficiency of 24.5%, which

is the highest energy conversion

efficiency ever reported by a sil-

icon cell made on a non-FZ

substrate. The PERT cell struc-

ture has demonstrated a remark-

able 83.5% fill factor from a 4.8

�-cm resistivity substrate, as a

result of the total rear boron

diffusion. This total rear diffu-

sion has also improved the rear

surface passivation and hence

resulted in high cell open-circuit

voltages. PERT cell features

have also been combined with

CZ(Ga) substrates which has

given an open-circuit voltage of

676 mV.

Also, all the PERT and PERL

cells made on MCZ(B) and

CZ(Ga) substrates have shown

stable performances after illumi-

in a 90-degree different direc-

tion. This enables all the light to

be internally reflected back into

the cell after the first double

pass. These light trapping

schemes have shown improved

long wavelength responses from

the cells, although no direct effi-

ciency improvement has been

observed yet. However, such

light trapping schemes are

expected to improve the effi-

ciency for cells on thinner sub-

strates such as in TPV cells and

concentrator cells, where light

trapping performance is more

critical.


FIGURE PV7: TWO NEW LIGHT TRAPPING STRUCTURES:

(A) BI-DIMENSIONAL SKEW, (B) QUILTWORK PATTERN.

FIGURE PV8: THE PERIPHERAL LOSS MECHANISMS IN A HIGH

EFFICIENCY SILICON PERL SOLAR CELL ARE: (A) LIGHT GENERATED

CARRIERS DIFFUSE INTO THE PERIPHERAL REGION; (B) OBLIQUE LIGHT

PASSES INTO THE PERIPHERAL REGION. APPLYING A GATE VOLTAGE,

VG, CAN CONSIDERABLE CHANGE THE SURFACE RECOMBINATION

VELOCITY IN THE DARK PERIPHERAL AREA.

NNoovveell LLiigghhtt TTrraappppiinngg DDeessiiggnnss

Two new light trapping schemes

have recently been developed at

UNSW. Figure PV7 shows these

structures as (a) bi-dimensional

skew and (b) quiltwork pattern.

The bi-dimensional skew struc-

ture results in more randomised

light passes by using two differ-

ent pyramid sizes to give con-

trolled offsets. The quiltwork

pattern ensures all the rear sur-

face reflected light returns to a

front area with grooves arranged

Research has also been conduct-

ed to use reactive ion etching to

fabricate deeper inverted pyra-

mid structures. With higher

slope in these deep inverted pyr-

amids, the light can enter the cell

surface with a larger entering

angle, which will allow the

light to travel and to be absorb-

ed closer to the surface

emitter. The high pyramid slope

will also make incident light

bounce more than 3 times on the

pyramid surfaces, to further

reduce the surface reflection.

(A) (B)

PV13 �

cells using a photolithographically

defined rear surface have achieved

open circuit voltages of 695 mV.

Consequently, the key goal in the high

efficiency buried contact solar cell

program is to develop new solar cell

structures with improved rear surfaces

and higher efficiencies. In 1999, the

high efficiency buried contact research

team focused on developing an analy-

sis technique to determine the pres-

ence and relative magnitudes of

recombination in solar cells (particu-

larly for floating junction passivation),

the development of boron back sur-

face fields and the development of a

thyristor solar cell.

Floating junction passivation has

demonstrated the ability to provide

very good rear surface passivation,

and buried contact solar cells using

Furthermore, a solar cell with a boron

BSF can easily be bifacial. An addi-

tional advantage of using boron BSF

passivation is that the process is very

similar to the commercial standard

buried contact solar cell, which has

been demonstrated have to lower

$/Wp cost than conventional com-

mercial solar cells.

High experimental open-circuit volt-

ages on lightly doped material indicate

the low effective surface recombina-

tion velocities achieved with a boron

BSF. For example, buried contact solar

cells on 10 �cm material have reached

645 mV, compared to 595 mV for an

alloyed Al-Si rear. These results are the

highest buried contact voltages

achieved on such high resistivity sub-

strates. In addition, the wafers main-

tained high short circuit currents and

suffered no minority carrier lifetime

degradation even with boron diffu-

sions as heavy as 7 �/�. SEM pho-

tographs in Figure PV12 show the

types of recombination mechanisms.

Of particular importance to high effi-

ciency solar cells is the identification

and analysis of a parasitic shunting

mechanism that acts like an injection-

level dependent rear surface recombi-

nation velocity. For example, Figure

PV11 shows an ideality factor curve,

from which the presence and magni-

tude of the parasitic shunt resistance

can be determined. This technique is

particularly useful for floating junction

devices, in which it is difficult to char-

acterise and analyse this resistance

using other techniques. Using the new

technique, lumped parameter values

for a parasitic shunt, can be quickly

determined for a broad range of float-

ing junction solar cells.

Although floating junctions can pro-

vide excellent surface passivation, the

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVTTIIEESS

� PV12

like continuous-sheet multicrystalline

silicon wafers, continue to appear on

the horizon; and manufacturers are

tending to use a broader variety of

feedstock wafers. Therefore, there is

considerable opportunity to develop

new solar cell processes and device

designs that are well matched to spe-

cific types of silicon wafers - process-

es and designs that enable high effi-

ciency in high-quality, higher-cost

wafers and vice versa (as shown in

Figure PV10). Thus, the BSCS activi-

ties are divided into two main research

areas: the High-Efficiency and

the Simplified Buried Contact solar

cell projects.

HHiigghh EEffffiicciieennccyy BBuurriieedd CCoonnttaaccttSSoollaarr CCeellllss

The many advantages and high effi-

ciency features of the top surface of

the standard buried contact solar cell

allow open circuit voltages close to

700 mV. For example, hybrid BC solar


FIGURE PV10: DEMONSTRATION OF RANGE OF BURIED CONTACT

(BC) SOLAR CELL STRUCTURES AND TYPES OF WAFERS TO WHICH

THEY ARE SUITED. THE SOLID LINES ARE MODELLING RESULTS AND

THE POINTS REPRESENT EXPERIMENTAL VALUES. THE PURPLE LINE/

POINTS REFERS TO A HIGH EFFICIENCY BURIED CONTACT STRUCTURE,

THE DOUBLE-SIDED BURIED CONTACT SOLAR CELL. THE BLUE LINES AND

POINTS REFER TO THE STANDARD BURIED CONTACT SOLAR CELL AND

THE RED LINE/POINTS ARE RESULTS FOR THE SIMPLIFIED BURIED

CONTACT SOLAR CELL STRUCTURE.

FIGURE PV11: GRAPH SHOWING THE EFFECT OF

VARIOUS RECOMBINATION MECHANISMS

ON THE IDEALITY FACTOR CURVE.

FIGURE PV12: COMBINED SEM

AND EBIC RESULTS COMPARING

BORON DIFFUSED AND AL-ALLOYED

REAR SURFACE ON AN N-TYPE SUB-

STRATE. THE WHITE REGIONS

SHOW THE JUNCTION BETWEEN

THE P-TYPE SUBSTRATE AND

N-TYPE BACK SURFACE FIELD. A)

BORON DIFFUSED BACK SURFACE

FIELD. B) AL-SI ALLOYED BACK

SURFACE FIELD.

Buried ContactResearch ReportUniversity Staff:

Dr Jeffrey Cotter,



(project leader),


Research Staff

Dr XiMing Dai, Dr Hamid Mehrvarz

Graduate Students

Linda Koschier (PhD), Keith

McIntosh (PhD), Bryce Richards

(PhD), Stephen Pritchard (PhD)

Alexander Slade (PhD), Bernhard

Vogl (Masters), Attachai

Ueranantasun (MsEngSci), Faruque

Hossain (MsEngSci)

U/graduate students

James Lee, Khairil Anwar

Kamarudin,Wee Chong Tan

Visiting Student

Manfred Fahr

The Buried Contact Solar Cell (BCSC)

group aims to develop new processing

technologies and device designs based

around the laser-groove grid electrode.

The established BCSC technology

continues to enjoy considerable suc-

cess in both the laboratory and the

commercial market. Figure PV9 shows

a recent application of BP-Solarex's

Saturn Modules installed during 1999

at the Sydney Olympic Village. The

Saturn Module is still the highest effi-

ciency, commercially available photo-

voltaic module.

The BCSC group has a broad spec-

trum of research and development

activities that address the evolving

nature of commercial silicon wafers.

Existing commercial silicon wafers

continue toward improved quality and

reduced cost; advances in sawing and

handling are leading to the use of

thinner wafers; new types of wafers,

FIGURE PV9: LIGHT TOWERS

AT THE OLYMPIC STADIUM IN

HOMEBUSH BAY USING BURIED

CONTACT MODULES PRODUCED

BY BP SOLAREX.

floating junction passivation have

achieved open circuit voltages of 687

mV. A key issue in analyzing such high

efficiency devices is the determination

of the presence and relative impact of

recombination mechanisms. Analysis

of the light J-V, dark J-V and Jsc-Voccurves and their second derivatives

(that is the m versus V or ideality fac-

tor curve) gives considerable insight

into the type and severity of several

flexibility inherent in the double-sided

BC solar cell also allows the study and

use of other passivation techniques.

Back surface field (BSF) passivation

using boron diffusion is an additional

option for rear surface passivation.

Boron back-surface-fieldpassivation

may be particularly desirable in situa-

tions where a high reflectivity at the

rear is desired - for example, in thin

wafers that require light trapping.

PV15 �

acteristic of two small pieces of the

same solar cell - one that does and one

that does not contain an area of junc-

tion punch-through. Modifying the

electroless nickel and copper deposi-

tion and sintering conditions has

proved to be successful in forming a

metal contact that has both low con-

tact resistance and minimal junction

punch-through. For example, 9 cm2

solar cells fabricated with a homoge-

neous emitter (at 50 �/sq.) have

exceeded 17% efficiency [Voc =

613 mV, Jsc = 34.8 mA/cm2. (not tex-

tured, SLAR: nr = 2.2), FF = 80.1%]

in commercially available Czochralski

silicon wafers. Stable fill factors over

79%, which is indicative of low con-

tact resistance and the absence of

junction punch-through, are achieved

regularly with the modified metallisa-

tion process. This result compares

favourably to standard BC solar cells

made with the same type of wafer, in

which 16.5% efficiency [Voc =

617 mV, Jsc = 33.4 mA/cm2 (not tex-

tured, SLAR: nr = 1.4), FF = 80.2%]

is regularly achieved.

The SBC team initiated a new project

area in 1999 focused on the develop-

ment of new solar cell fabrication

processes based on spray-hydrolysis

deposited titanium dioxide. Although

thin films of titanium dioxide have

been developed for a variety of pur-

poses, their use within the PV industry

is almost exclusively limited to anti-

reflection coatings. In work that is in

the process of being published, the

team will demonstrate the film's

chemical resistance to most common

wet chemical etches, the selective dep-

osition of it on the surface without

coating inside laser grooves, its suit-

ability as a electroless metal plating

mask, use of it during high-tempera-

ture processing with no contamina-

tion of either wafer or furnace and it's

ability to passivate lightly diffused n-

type emitters to a degree suitable for

� the crystallisation of amor-

phous silicon (a-Si) films on

glass at low temperature (<

600 °C) using metal-induced

crystallisation and the char-

acterisation of the resulting

polycrystalline silicon films,

� the development of a surface

texture method for glass

substrates,

� the investigation of the light

trapping properties of amor-

phous silicon films deposited

on textured glass substrates,

� experimental studies evaluating

the feasibility of the ion-assisted

deposition method for the fabri-

cation of polycrystalline silicon

solar cells on glass, and

� fundamental experimental in-

vestigations of the parallel multi-

junction thin-film silicon solar cell,

a novel device structure recently

conceived at UNSW and present-

ly being commercialised by Pacific

Solar in Sydney.

MMeettaall-iinndduucceedd CCrryyssttaalllliissaattiioonn ooff SSiilliiccoonn

One of the most challenging prob-

lems for the development of poly-

crystalline silicon thin-film solar cells

is the growth of crystalline silicon

on foreign, low-cost and low-tem-

perature substrates. We are investi-

gating aluminum-induced crystalli-

sation (AIC) as an alternative

process to the commonly used

processes such as laser crystallisation

and solid phase crystallisation (SPC).

Using AIC, we have achieved sub-

stantially faster crystal growth than

SPC and crystal grains larger than in

laser crystallised material. The phe-

nomenon of the AIC as studied in

our group is that adjacent aluminum

and amorphous silicon layers

exchange places when heated at a


� PV14

being developed specifically for

Czochralski and multicrystalline

wafers. Solar cell performance in these

types of wafers is primarily limited by

the electrical quality of the wafer itself,

and therefore, there is considerable

scope to simplify the fabrication

process without a loss in performance.

In 1999, the team continued work on

the development of a homogeneous

emitter process that eliminates two of

four high-temperature process steps

from the standard BC process. In

addition, the team introduced two

new initiatives: (1) the expansion of

the capabilities of titanium dioxide

beyond its use as an antireflection

coating, and (2) the development of

novel processes to be used in a low-

cost, rear surface structure, specifically

for thin silicon wafers.

One of the key issues associated with

the use of a homogeneous emitter is

selecting the optimal diffusion profile

that minimises emitter and groove

recombination, that minimises contact

resistance, and that avoids junction

punch-through after contact sintering.

Previous work demonstrated that the

total emitter (emitter and groove) dark

emitter saturation current is

minimised (typically, Joe = 250 fA/cm2)

physical difference between the boron

and aluminum back surface field.

An additional method for surface pas-

sivation of the rear is to use a thyris-

tor-structure solar cell. Figure PV13

shows the schematic of a thyristor

structure solar cell. The thyristor solar

cell uses its multiple junctions for two

purposes. Under illumination, the inci-

dent light and the forward bias of the

top junction ensure that all the junc-

tions are forward biased, thus allowing

the light generated current to pass

through the solar cell while also passi-

vating the rear surface. In the dark, the

thyristor solar cell does not allow cur-

rent flow, and thus each individual

solar cell acts as a blocking diode. Ex-

perimental thyristor solar cells exhibit

higher open-circuit voltages compared

to identical devices with an aluminum

sintered rear surface.

SSiimmpplliiffiieedd BBuurriieedd CCoonnttaacctt ((SSBBCC))SSoollaarr CCeellllss

The SBC team is pursuing a variety of

nov technologies that can potentially

reduce the cost of processing while

retaining the efficiency potential of

laser-grooved front grid electrodes.

The SBC technology is presently

at a sheet resistance of about

50-70 �/sq. for typical surface passi-

vation conditions. Also, the short cir-

cuit current is relatively independent

of the emitter sheet resistance down

to about 40 �/sq.

Work on the homogeneous emitter in

1999 focused on developing the

groove metal deposition and sintering

conditions to minimise contact resist-

ance and to avoid junction punch-

through. The standard nickel/copper

plating and sintering process requires

a heavily diffused groove for low con-

tact resistance and minimal shunting.

While this process results in accept-

ably low contact resistance for lightly

diffused grooves (equivalent to a spe-

cific series resistance of less than 0.2

�-cm2), the resulting electrodes are

shunted by small-area, localised metal-

silicon rectifying junctions, where the

nickel has punched through the emit-

ter to contact the p-type silicon. Figure

PV14 shows the current-voltage char-


FIGURE PV14: CURRENT- VOLT-

AGE CHARACTERISTICS OF TWO

PIECES CUT FROM A SINGLE

SOLAR CELL. THIS ILLUSTRATES

THE LOCALISED NATURE OF

JUNCTION PUNCH-THROUGH IN

A LIGHTLY DIFFUSED

GROOVE (45 �/�).

Czochralski silicon wafers. The SBC

team also initiated a new project area

in 1999 focused on novel, low-cost,

rear-surface structures for thin silicon

wafers. Staff and students working in

this project area are examining the

suitability of forming an aluminum-

silicon contact in the shape of a grid

electrode using a laser beam to effect

the alloying process, as well as the

development of pigmented diffuse

rear-surface reflectors to enhance the

light trapping of solar cells fabricated

on thin silicon wafers.

Thin-Film GroupUniversity Staff:

Dr Armin Aberle (group leader),



Research Fellows:

D. Pietro Altermatt,

Dr Patrick Campbell,

Dr Mark Keevers (project leader

parallel multijunction cells),

Dr Ramakant Kumar (05/99 - 07/99),

Dr Tom Puzzer

Graduate students:

Nils-Peter Harder (PhD),

Oliver Nast (PhD; to 11/99),

Dirk-Holger Neuhaus (PhD),

Nicholas Shaw (PhD),

Johnny Wu (Masters)

U/graduate students:

Kah Mun Thong (to 11/99),

Chun Cheong Wong (to 11/99),

Chee Bon Tan (since 07/99)

Visiting Students:

Martin Boettcher (12/99),

Christian Haase (12/99)

The primary aim of the thin-

film group is to develop poly-

crystalline thin-film silicon solar

cells on glass, an approach that

is widely recognised as being a

pathway towards substantially

lowering the cost of solar cells.

In 1999, our main areas of work

have been:

FIGURE PV13: SCHEMATIC OF A THYRISTOR STRUCTURE SOLAR CELL.

PV17 �

grain structure, and (vi) the Al/a-Si

interface. The results of these stud-

ies are presently used to optimise

the crystallisation process. This may

ultimately lead to the realisation of

high-quality poly-Si films on glass

at low temperature that are suitable

for the subsequent fabrication of Si

thin-film solar cells.

FFaabbrriiccaattiioonn ooff aa SSuurrffaacceeTTeexxttuurree ffoorr GGllaassssSSuubbssttrraatteess

Our previous modelling studies have

shown that a silicon thin-film solar cell

conformally deposited on a textured

substrate can provide both very effec-

tive light trapping and very effective

reduction of front surface reflection

losses. We have developed a method

to accurately emboss a surface texture

into glass. The method consists of

heating glass to a workable viscosity

and then pressing a texture into its sur-

face with a textured die. We have been

using a silicon wafer as the die. The sil-

icon wafer is textured with inverted

pyramids (side length 10 �m) and rein-

forced by bonding its rear side to

another silicon wafer. An inert ceram-

ic coating is used to isolate the highly

reactive heated glass surfaces from

supports and the die. We are currently

installing a gimbal joint in the pressing

apparatus to improve the uniformity

of the texture. A scanning electron

micrograph of a pressed glass texture

is shown in Figure PV18.

LLiigghhtt TTrraappppiinnggMMeeaassuurreemmeennttss

The accuracy of current optical

and spectral response methods

used to measure the light trap-

ping properties of a sample are

severely limited by parasitic

effects. We developed a way

around this by measuring the

relative enhancement of the


� PV16

in the range 350 to 525 °C. Thus,

simple and industrially relevant

deposition and processing techniques

are employed.

Figure PV15 shows the effect of

the layer exchange when adjacent

layers of Al and a-Si are annealed

at low temperature. The Al that

segregated to the top of the

structure during the crystallisa-

tion process can be selectively

etched off. The resulting struc-

temperature well below the eutectic

temperature of 577 ºC of the Si/Al

binary system. During the exchange

process, a polycrystalline silicon layer

is formed at the original position of

the Al film. The Al/Si layered struc-

ture is fabricated on glass substrates

(Corning 1737). The Al and a-Si are

deposited by thermal evaporation

and dc magnetron sputtering, respec-

tively. The crystallisation takes place

during a subsequent isothermal

annealing process at a temperature

ture is a continuous polycrys-

talline silicon film on glass. The

crystallographic properties of

these poly-Si films were investi-

gated using Raman spectroscopy,

secondary electron microscopy

(SEM), transmission electron

microscopy and in-situ optical

microscopy.

Figure PV16 shows a comparison

of Raman spectra taken on a crys-

talline Si wafer and a poly-Si layer

formed by AIC at 500 °C. The

close agreement of the two spectra

is an indication of the high crystal-

lographic quality of our polycrys-

talline material.

The structure and size of the grains

of the poly-Si material can be stud-

ied when the Si films are separated

from the glass substrate by means

of chemical etching. This prepara-

tion enables the investigation of

clean and smooth surfaces. Figure

PV17 shows an electron chan-

nelling SEM image of such a poly-

Si film, revealing grain sizes above

10 µm. The electrical properties of

the poly-Si films were investigated

using Hall effect measurements.

According to these experiments,

which were performed in coopera-

tion with the Hahn Meitner

Institute, Berlin, the material is of

p-type character due to high doping

with Al atoms (~2 ��1018 cm-3).

The AIC work conducted in 1999

focused on various process param-

eters that influence the exchange of

the Al and Si layers during the crys-

tallisation, and consequently have

an impact on the final characteris-

tics of the poly-Si film. The param-

eters that seem to have a major

influence on the overall process are

(i) the annealing time, (ii) the layer

thickness ratio, (iii) the temperature,

(iv) the layer sequence, (v) the Al


FIGURE PV16: RAMAN SPECTRA OF A POLYCRYSTALLINE SAMPLE AND, FOR

COMPARISON, A POLISHED SINGLE CRYSTALLINE SI WAFER. EACH SPEC-

TRUM IS NORMALISED TO ITS MAXIMUM VALUE.

FIGURE PV17: ELECTRON

CHANNELLING SEM

IMAGE OF THE FORMER

POLY-SI/GLASS INTERFACE OF

FULLY CRYSTALLIZED SAMPLES

ANNEALED AT 500 ºC.

FIGURE PV18: SCANNING

ELECTRON MICROGRAPH OF

A GLASS PANE UNIFORMLY

TEXTURED WITH UPRIGHT

PYRAMIDS, FORMED BY PRESSING

A SILICON WAFER COVERED WITH

INVERTED PYRAMIDS ONTO THE

GLASS AT HIGH TEMPERATURE

AND PRESSURE. (PICTURE TAKEN

BY TOM PUZZER)

photoconductance of undoped

hydrogenated amorphous silicon

films deposited on textured and

untextured glass substrates,

respectively. At present we are

investigating the light trapping

properties of 10 �m thick a-Si

films, as for thinner films the

accuracy of this method is

severely reduced due to the para-

sitic surface recombination

effect. We are also developing

suitable surface passivation tech-

niques for a-Si, allowing us to

extend the method to

thinner films.

TThhiinn-FFiillmm SSiilliiccoonn SSoollaarr CCeellllss oonnGGllaassss bbyy IIoonn-AAssssiisstteedd DDeeppoossiittiioonn((IIAADD))

The major aim of the thin-film

approach to solar cells is cost reduc-

tion while maintaining good efficien-

cy. Therefore, it is crucial to develop

processes that are compatible with

FIGURE PV15: CROSS-SECTIONAL FOCUSED ION BEAM MICROGRAPHS

OF THE A-SI/AL/GLASS STRUCTURE: (A) BEFORE ANNEALING; (B) AFTER

ANNEALING FOR 30 MIN AT 500�C; AND (C) SEM MICROGRAPH AFTER

AL ETCHING, EXPOSING THE CONTINUOUS POLY-SI LAYER. NOTE THE

SAMPLES ARE TILTED IN THESE MICROGRAPHS [45� IN (A) AND

(B) AND 20� IN (C)], SO THE SCALES ARE ONLY VALID IN THE HORIZONTAL

DIRECTION. THE SHORT WHITE DOTTED LINE IN (C) IS A GUIDE TO THE EYE.

PV19 �

have efficiencies up to 13 %, with

Voc, Jsc and FF values typically

around 630 mV, 24 mA/cm2 and

78 %, respectively.

The development of a baseline

process for the fabrication of

PMJ test-bed cells opens up a

wealth of opportunities for the

systematic investigation of PMJ

cell performance and its limiting

mechanisms, such as junction

recombination, and the implica-

tions of various cell design and

processing options, particularly

those likely to be of more com-

mercial relevance, such as laser

scribing, laser doping, rapid

thermal processing and electro-

less metal plating.

As a first experimental study of PMJ

cells, we have systematically investigat-

ed the impact of poor material quality

on cell performance using 10 MeV

proton irradiation to controllably

degrade the silicon quality in complet-

ed PMJ cells from its initial “pristine”

state. As Figure PV23 shows, the PMJ

cell clearly exhibits a greater radiation

tolerance than identically processed

single-junction (SJ) cells. This indi-

isolation trenches, with interdigitat-

ed n- and p-type buried contact grids

of about the same depth. Only one

type of multilayer stack has been

avail-able for the project to date. It

consists of n-p-n-p-n epilayers

(17 �m total, doped 1017 cm-3) on a

p+ buffer layer (15 �m thick,

doped 1018 or 1019cm-3) fabricated

on a p+ single-crystal CZ wafer

(630 �m thick, 0.01 �cm).

The processing sequence devel-

oped to fabricate these PMJ test-

bed cells is based on photolithog-


� PV18

talline silicon wafers as substrate,

the company ANTEC in Germany

has already proven that IAD is

capable of providing high-quality

crystalline silicon films. In 1999 we

have started a cooperation with

ANTEC, enabling us to perform

first experimental studies using

ANTEC equipment in Germany.

Figure PV19 shows the main fea-

tures of an IAD system. After the

silicon atoms are ionised, they can

be accelertaed towrds the substrate

using an electric field. This addition-

al energy enables the deposited sili-

con atoms to take over the crys-

talline order of the substrate even at

low temperatures. When using glass

as a substrate, it has to be coated by

a silicon layer that can act as a seed

for the subsequent growth of good

quality polycrystalline silicon. As

discussed above such as seeding

layer has already been developed by

our group using aluminium-induced

crystallisation.

PPaarraalllleell MMuullttiijjuunnccttiioonn TThhiinn-ffiillmm SSiilliiccoonn SSoollaarr CCeellllss

The parallel multijunction (PMJ)

thin-film silicon solar cell, shown in

cheap substrate materials (e.g. stan-

dard glass). The use of standard

glass restricts cell processing to rel-

atively low temperatures of below

about 600° C. For most thin-film

technologies, this restriction leads

to comparatively low material quali-

ty, a drawback that can only be com-

pensated for using specialised cell

structures such as the parallel multi-

junction cell discussed below. In

contrast to this approach (which is

followed by the company Pacific

Solar in Sydney), the thin-film

group at UNSW is aiming at devel-

oping a process for high-quality

Figure PV20, theoretically enables

high efficiency on low-cost, poor-

quality polycrystalline silicon.

Commercialisation of this exciting

new technology is currently being

undertaken by Pacific Solar in

Sydney. Here at UNSW, one research

strand is focussing on a more funda-

mental study of this novel device

structure, with a particular emphasis

on quantifying the impact of materi-

al quality on cell performance.

The initial focus of this work was

the fabrication of PMJ test-bed

devices amenable to systematic

experimental studies of this rather

complex cell structure but still con-

taining the essential features of the

PMJ cell - namely a multilayer stack

of n- and p-type silicon layers, and

buried contact grooves which elec-

trically connect all like-polarity layers

in parallel. The PMJ test-bed cells

fabricated are shown schematically

in Figure PV21. These cells are

made from commercially available

high-temperature CVD epilayers

grown on highly doped single-crys-

tal silicon wafers (rather than the

glass superstrate of Figure PV20.

The cells are 1-cm2 mesa-shape

devices separated by 25 �m deep


FIGURE PV20: THE PARALLEL MULTIJUNCTION THIN-FILM SILICON CELL,

CONSISTING OF ALTERNATING POLARITY N- AND P-TYPE LAYERS, WITH LIKE-

TYPE LAYERS CONNECTED IN PARALLEL USING A BURIED CONTACT GRID.

FIGURE PV21: SCHEMATICS OF THE ACTUAL PMJ CELLS FABRICATED ON SINGLE-CRYSTAL WAFER

SUBSTRATES FOR THIS MORE FUNDAMENTAL STUDY: (A) CROSS-SECTIONAL VIEW; (B) TOP VIEW.

FIGURE PV22: PARALLEL ELECTRICAL CONNECTION OF LIKE-POLARITY

SILICON LAYERS IS SHOWN IN THESE CROSS-SECTIONAL EBIC/SE

IMAGES OF AN N- AND P-TYPE FINGER IN A PMJ CELL. THE BRIGHT

REGIONS INDICATE THE p-n JUNCTIONS.

(A) (B)

raphy, anisotropic wet etching,

high-temperature oxidations and

diffusions, and evaporated metalli-

sation. Critical to the fabrication of

the present devices is the use of a

thick photoresist required for

adequate coverage of the device's

25 �m deep vertical features.

Evidence for successful parallel

electrical connection of like-polari-

ty layers is clearly shown in the

cross-sectional EBIC/SE (elec-

tron-beam-induced current/sec-

ondary electron) images of Figure

PV22 . The fabricated PMJ cells

FIGURE PV19: SCHEMATIC REP-

RESENTATION OF AN ION-

ASSISTED DEPOSITION (IAD)

SYSTEM FOR THE FABRICATION

OF GOOD-QUALITY POLYCRYS-

TALLINE SILICON FILMS AT LOW

TEMPERATURE (< 600��C).

polycrystalline silicon films on glass

at low temperature (< 600 °C).

One of the silicon growth/deposi-

tion methods that we are investigat-

ing is “ion-assisted deposition”

(IAD). Using elevated temperatures

in the 600 - 800 °C range and crys-

PV21 �

Research Fellows:

Dr Pietro Altermatt

Dr Patrick Campbell

Dr Richard Corkish

Dr Mark Keevers

Graduate Students:

Stephen Bremner (PhD), Didier

Debuf (PhD), David Fuertes Marrón

(Masters), Keith McIntosh (PhD),

Dirk-Holger Neuhaus (PhD),

Nicholas Shaw (PhD)

Undergraduate Students:

Kah Mun Thong (to 11/99),

Kee Meng Wee (to 01/99)

Visiting Students:

Marco Lammer (to 04/99),

Jürgen Schumacher (to 06/99).

EEBBIICC MMooddeelllliinngg

The three-dimensional numerical

electron beam induced current

(EBIC) model used previously to

study grain boundaries in mul-

ticrystalline silicon has been

adapted to simulate the response

to an electron beam scanning

across the edge of a solar cell. The

aim is to determine both bulk and

surface recombination parameters

from experimental scans by com-

parison with comprehensive and

reliable simulations. In the past,

analytical expressions have been

used for this purpose. Those

expressions have, by necessity,

involved more simplifications

than are needed in this work. As a

representative example, Figure

PV25 shows a two-dimensional

section from a three-dimensional

numerical simulation of the inter-

action of a narrow electron beam

with a Si solar cell. For these sim-

ulations the solar cell was rotated

anti-clockwise by 90°, so that the

cell edge faces the incoming elec-

tron beam. The blue region on the

HHeeaavvyy DDooppiinngg EEffffeeccttss iinn SSiilliiccoonn

The introduction of dopants into

the silicon crystal changes its den-

sity of states (DOS). Usually, heav-

ily doped silicon has been mod-

elled using solely the ideal DOS of

undoped silicon, regardless of the

doping level. However, this crude

PPHHOOTTOOVVOOLLTTAAIICCSS SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE � 11999999 AACCTTIIVVTTIIEESS

� PV20

cates that, in addition to terrestrial

applications, PMJ cells are also well

suited for space applications. The

superior efficiency of the PMJ cells in

heavily defected silicon (lifetimes as

low as 10 ps) is the first experimental

demonstration of their predicted

performance advantage in poor-

quality material.

QQuuaannttuumm WWiirreess iinn SSiilliiccoonn

In addition to the thin-film solar cell

work described above, we are also

investigating new methods of fabri-

cating quantum wires in silicon. Such

wires are a key feature of upcoming

nanoscale semiconductor devices.

Such low-dimensional structures may

also have application to advanced

solar cell designs. As yet, such wires

have only been realised using sophisti-

cated approaches and, in general,

expensive semiconductor materials. In

contrast, in this project we aim at fab-

ricating quantum wires in today's stan-

dard material, silicon, using a striking-

ly simple approach that is compatible

with the mainstream microelectronics

industry. The basic idea of the

Theory Group

University Staff:

Dr Armin Aberle (group leader)

Dr Jeff Cotter


A/Professor Gernot Heiser




FIGURE PV25: CALCULATED BULK CARRIER RECOMBINATION RATE

IN A SHORT-CIRCUITED SILICON SOLAR CELL 'ILLUMINATED' FROM

THE SIDE WITH A NARROW ELECTRON BEAM. THE CELL IS ROTATED

ANTI-CLOCKWISE BY 90°, SO THAT THE EMITTER (DARK BLUE

REGION) RUNS VERTICALLY.

FIGURE PV26: CALCULATED SHORT-CIRCUIT CURRENT OF THE

SILICON SOLAR CELL OF FIGURE PV25 AS A FUNCTION OF THE

ELECTRON BEAM DISTANCE FROM THE JUNCTION AND THE SURFACE

RECOMBINATION VELOCITY (SRV) OF THE CELL EDGE. THE BULK

ELECTRON LIFETIME IS THE SAME FOR ALL CURVES (20 NS).

left represents the emitter of the p-

n junction cell. The electron beam

enters the cell 10 �m away from

the junction. Figure PV26 shows

the corresponding short-circuit

current of the solar cell as a

function of the electron beam dis-

tance from the junction and the

surface recombination velocity of

the cell edge.

FIGURE PV23: COMPARISON OF (A) SHORT-CIRCUIT CURRENT AND (B) EFFICIENCY DEGRADATION OF

IDENTICALLY PROCESSED PMJ AND SINGLE-JUNCTION SILICON SOLAR CELLS IRRADIATED WITH 10 MEV

PROTONS. PERL CELL DEGRADATION IS ALSO SHOWN FOR COMPARISON.

(A) (B)

approach is the one-dimensional local-

isation of electrical charges within an

insulator on a silicon wafer by means

of an atomic-resolution microscope.

By creating a sufficiently large charge

density, a quantum wire with unprece-

dented structural fineness can be

induced in the silicon. As insulator we

are using a double-layer stack consist-

ing of an ultra-thin (~1.5 nm) thermal

oxide and a plasma silicon nitride film.

FIGURE PV24: SHOWS A SCHEMATIC REPRESENTATION OF

THE SAMPLES INVESTIGATED IN THIS PROJECT.

PV23 �

theory, while the carrier lifetime

measurements were performed at

the ANU. In the course of this

work, the Auger recombination

rate has also been calculated and

measured under high-injection

conditions, and we found good

agreement with results previously

published by other groups. This

opens up possibilities for develop-

ing a general Auger model, which

will be valid under all relevant

combinations of dopant and injec-

tion densities.

AAddmmiittttaannccee SSppeeccttrroossccooppyy

In this project, we improve the

understanding of the admittance

of various device structures: sin-

gle-crystalline cells and multi- or

poly-crystalline cells, partly made

as thin films. In order to establish

a firm basis, we initially investigat-

ed only the imaginary part of the

admittance (i.e. the capacitance),

because much work has been pub-

lished in this field. We determined

the influence of the Gaussian

emitter profile on the capacitance,

and compared it to the case of an

“abrupt high-low junction”,

which is extensively treated in the

literature. We simulated the admit-

tance with the software Dessis,

where the small-signal AC analysis

was recently implemented and was

still in its test phase. We found

excellent agreement between our

simulations and our measure-

ments. This helps to understand

how the small-signal analysis

needs to be combined with the

boundary conditions of the simu-

lations. We also found that, when

extracting the dopant profile from

C-V measurements, some com-

monly used data evaluation proce-

dures (based on the depletion

region approximation) may lead to

significant errors.

As described above and in last

year's Annual Report, we have

successfully introduced Schenk's

bandgap narrowing model to

device simulation. This model

enables us to simulate highly

doped regions using Fermi sta-

tistics for the free carrier distri-

bution. This is a major concep-

tual improvement because, so

far, the effect of Fermi degener-

acy has only been partly includ-

ed in device modelling by the

“apparent bandgap” concept,

contributing, to significant dis-

crepancies between simulated

and experimental open-circuit

voltages of silicon cells with

highly doped emitters. Schenk's

bandgap narrowing model

enables us to separate degenera-

cy and band shrinkage effects in

the interpretation of saturation

current measurements. This

allows us to derive S values that

are based on a sounder theory.

SSiimmuullaattiioonn ooff PPrroottoonn-IIrrrraaddiiaatteedd SSiilliiccoonn SSoollaarrCCeellllss

One way to understand and

quantify losses induced by crys-

tal defects in thin-film solar cells

is to irradiate monocrystalline

cells with protons in a con-

trolled manner. We irradiated

monocrystalline PERL cells and

simulated their current-voltage

(I-V) curves and quantum effi-

ciency behaviour. We showed

that changes in both the recom-

bination rate and the diffusion

length can be described with the

Shockley-Read-Hall formalism,

using a defect energy level of

Ec - 0.42 eV, corresponding to

the 0/- charge state of the diva-

cancy, in agreement with publi-

cations from IMEC, Belgium.

As expected, we observed that

IInnttrriinnssiicc CCaarrrriieerr DDeennssiittyy

The commonly used value for the

intrinsic carrier density ni of crys-

talline silicon is 1.00 ��1010 cm-3 at

300 K. This value was experimen-

tally determined by A. Sproul and

M. Green in 1990, using specially

designed solar cells. However, more

recent measurements by Misiakos

and Tsamakis gave a slightly lower

ni value of 9.7 ��109 cm-3. We re-

evaluated the measurements of

Sproul and Green, using the device

simulator Dessis and a new quan-

tum-mechanical model for

bandgap narrowing developed by

Andreas Schenk from ETH

Zurich. We found that the experi-

ment by Sproul and Green was

influenced by bandgap narrowing,

despite the low dopant density

(1014 to 1016 cm-3) of their samples.

Our new interpretation provided

an ni value of 9.65 �� 109 cm-3 at

300 K, which is consistent with the

work of Misiakos and Tsamakis on

a lightly doped substrate.

SSuurrffaaccee RReeccoommbbiinnaattiioonn aatt tthhee EEmmiitttteerr SSuurrffaaccee

In contrast to lowly doped surfaces

(e.g., at the rear of PERL cells), the

surface recombination velocity S of

highly doped surfaces (e.g. the sur-

face of the emitter of silicon cells) is

only indirectly accessible. This is so

because S of the emitter surface is

usually extracted from measure-

ments of the emitter saturation cur-

rent, where losses in the emitter bulk

region are included and need to be

subtracted. The losses in the bulk

region of the emitter are not well

understood, as the inconsistencies

among the numerous publications

on this topic indicate. Hence, differ-

ent models for the emitter bulk loss-

es lead to different S values deter-

mined for the emitter surface.


� PV22

resistance of the sample. Figure

PV28 shows the data obtained

for a phosphorus doping level

of about 1 ��1019 cm-3. The local

minimum visible in this data

(see insert) indicates the exis-

tence of an impurity band that

approximation fails in particular

for the heavily doped emitter and

back-surface-field regions of crys-

talline silicon solar cells, resulting

in an overestimation of its open-

circuit voltage. We calculated the

DOS of phosphorus-doped sili-

con, using photoluminescence

data of Bergensen et al. and

Schenk's quantum-mechanical

bandgap narrowing model. Figure

PV27 shows our results (symbols),

together with an empirical para-

meterisation (lines) of the DOS at

four different doping levels. This

technique allows us to determine

the DOS for doping densities

below 1 ��1019 cm-3. However, the

DOS of more heavily doped sili-

con cannot be extracted with suffi-

cient precision from photolumi-

nescence measurements.

In order to determine the DOS

of more heavily phosphorus-

doped silicon, we performed

low temperature (4.2 K) tunnel

spectroscopy measurements on

Schottky diodes. These meas-

urements determine the voltage

dependence of the differential

phosphorus-doped silicon from

these tunnel spectroscopy ex-

periments. This is expected

to lead to a further refinement

of the DOS parameterisation

shown in Figure PV27.

AAuuggeerr RReeccoommbbiinnaattiioonn

In a collaboration with Dr Jan

Schmidt and Mark Kerr from

the Australian National Uni-

versity (ANU) in Canberra, we

are investigating Auger recombi-

nation at intermediate injection

conditions, where the density of

injected carriers is similar to the

dopant density. This is the injec-

tion regime where most Si solar

cells operate. However, little is

known about Auger losses in

this regime because it is rather

difficult to measure or calculate

the Coulomb-enhanced Auger

recombination rate at such injec-

tion levels. The reasons are non-

linear charge carrier screening

effects and the influence of an

injection level dependent surface

recombination velocity. Screening

effects have been investigated in a

collaboration with Dr Andreas

Schenk from the ETH Zurich,

using the Thomas-Fermi screening


FIGURE PV27: AN EMPIRICAL PARAMETERISATION OF THE DOS

OF PHOSPHORUS-DOPED SILICON (SOLID LINE), OBTAINED FROM

PHOTOLUMINESCENCE MEASUREMENTS.

FIGURE PV28: DIFFERENTIAL RESISTANCE AS A FUNCTION OF

VOLTAGE, OBTAINED FROM TUNNEL SPECTROSCOPY MEASUREMENTS

ON A SCHOTTKY DIODE FABRICATED ON HEAVILY PHOSPHORUS-DOPED

SILICON. THE RESISTIVITY OF THE SILICON IS 0.0053 �CM, CORRESPON-

DING TO A DOPING LEVEL OF ABOUT 1 �� 1019 CM-3.

is still clearly separated from the

silicon conduction band, despite

the rather large doping level.

Using a new data evaluation

method, we are currently calcu-

lating the DOS of heavily

PV25 �

Additional transport mechanisms

are difficult to include in

“detailed balance” modelling

approaches that assume uniform

material and constant quasi-

Fermi levels, implying that carri-

ers can move “instantaneously”

and hence transport mechanisms

are not relevant. In order to

include transport, the device

must be divided into separate

sections, with transport across

the interfaces. Formulation of

this theoretical approach is con-

tinuing. Figure PV29 shows opti-

mised efficiency for a quantum

well solar cell, including hot car-

rier transport across the well and

Figure PV30 shows how the

solar cell efficiency for a single

device (only radiative recombina-

tion is considered) varies as the

fraction of carriers scattered into

the well increases. At f=1 (all car-

riers can be scattered into the

bottom of the well), the efficien-

cy equals that calculated for

tandems or the IPV effect, but

devices with hot carriers, the effi-

ciency can be higher.

dures and regulations for their

use are required. To ensure mar-

ket equity, energy market reform

must continue, removing biases

towards supply side and cen-

tralised options and ensuring

environmental and social issues

are considered in decision mak-

ing. Consistent industry, taxa-

tion and energy policies are

needed, with a long-term focus

on sustainability. Information is

needed for customers and plan-

ners on renewable resources,

technologies and systems.

To address price differentials,

R&D is needed on improved

production processes and lower

cost products, while market sub-

sidies are needed until target

penetration levels are reached.

Governments should purchase

renewables for their own use,

impose emission taxes on fossil

fuels and underwrite financing

packages to encourage confi-

dence and take-up.

Finally, the successful develop-

ment of a viable and robust

renewables industry in Australia

requires a comprehensive educa-

tion strategy, including familiari-

ty at community and school

level, technical skills for installa-

tion and maintenance and pro-

fessional training for designers,

engineers, architects and plan-

ners. The Key Centre is well

placed to address some of these

education requirements.

RReenneewwaabbllee EEnneerrggyy PPoolliiccyy GGrroouupp

In a joint UNSW/ACRE project,

Dr Watt is leading an ACRE

Renewable Energy Policy Group

(AEPG), with Professor Outhred

also a Group member. The AEPG


� PV24

in the depletion region to the

behaviour of I-V curves are far

too approximate. With our more

general model, we were able to

reproduce the experimentally

observed maximum in the ideal-

ity factor of the I-V curves. It is

noted that this maximum ideali-

ty factor is well below the com-

monly assumed value of 2. We

also clarified why the ideality

factor decreases with increasing

cell voltage. Currently, we are

investigating losses where the

p-n junction reaches the surface,

and are extending our model to

grain boundaries crossing the p-

n junction.

QQuuaannttuumm WWeellll SSoollaarr CCeellllss

An investigation is being made

into the potential for novel solar

cell designs, such as the inclusion

of quantum wells, to increase the

theoretical efficiency limits of

homojunction solar cells. A key

issue surrounding quantum well

solar cells has been the conflict-

the density of such defects is

linear with proton flux, with an

introduction rate agreeing with

that reported by various re-

search groups.

These experiments provide a basis

for the quantification of losses in

parallel multijunction cells. We irra-

diated such cells as well, made of

high-purity crystalline material, in

the same manner as the PERL

devices mentioned above (see thin-

film reports). We are currently locat-

ing and quantifying loss mechanisms

related to the parallel multijunction

structure, in particular the impact of

p-n junction depletion region recom-

bination. This study will allow us to

better understand the performance

of such cells, and to quantify advan-

tages compared to commonly used

single-junction cells.

RReeccoommbbiinnaattiioonn iinn tthheeJJuunnccttiioonn DDeepplleettiioonn RReeggiioonn

Recombination in the p-n junc-

tion depletion region may be the

limiting loss mechanism in thin-

film cells, as this region extends

over a relatively large volume of

such devices. We simulated the

influence of depletion region

recombination on the I-V

curves by means of numerical

modelling. Using Dessis, we

solve the fully coupled semicon-

ductor equations without the

restricting assumptions often

found in literature (such as the

depletion region approximation,

assumptions on the quasi-Fermi

levels, etc.). We are also able to

numerically calculate recombi-

nation rates arising from more

than one defect level, as well as

from trap-assisted tunnelling.

We found that most analytical

models that relate Shockley-

Read-Hall recombination losses

ing modelling, particularly

detailed balance modelling, in

some cases supporting an effi-

ciency increase and in some case

showing that no efficiency

increase is possible. The key

implication of our modelling is

that it establishes criteria in the

search for devices that exceed

existing efficiency limits. It

demonstrates that in order for a

two-terminal solar cell to exceed

homojunction efficiency limits, it

must have features that allow

more than a single quasi-Fermi

level to exist within the device.

For example, two-terminal tan-

dem devices, which have experi-

mentally exceeded homojunction

efficiency limits, can do so since

the tunnel junction connecting

the various regions allow multi-

ple quasi-Fermi levels to exist.

Other methods by which multi-

ple quasi-Fermi levels can be

achieved are the impurity photo-

voltaic (IPV) effect and alterna-

tive transport mechanisms at

interfaces.


Renewable Energy Policy and Planning

University Staff:

Associate Professor Hugh Outhred

Project Staff:

Dr Muriel Watt

PPoolliiccyy RReeppoorrtt

A detailed study was prepared

for the Australian Cooperative

Research Centre for Renewable

Energy (ACRE) on “Policy

Options for Enhancing Elec-

tricity Industry Sustainability in

Australia”. In summary, the

report concludes that the critical

problems facing renewables in

Australia lie with market distor-

tions and lack of infrastructure,

both of which require a long-

term policy focus and consistent

industry support.

To ensure renewables can gain

market access, standard proce-

FIGURE PV29: OPTIMISED EFFICIENCY AS A FUNCTION OF THE OVERALL

BAND GAP, EG1, WITH F=0.5. EG2 IS THE WELL BANDGAP. FIGURE PV30: IMPACT OF TRANSPORT FACTOR, F, ON EFFICIENCY.

PV27 �

ment (to the pre-commercial

stage) of specialised equipment

for solar PV applications.

Notable users of the Centre's

DAD have been:

� ECO Design Foundation

General Technology

� Sussan

� Taronga Zoo

� National Parks and Wildlife

Service

� Harry Seidler and Associates

� Barry Webb and Associates

� energyAustralia

� Olympic Organising

Committee

� Federal Ministry of Health,

India

� Kenhill Engineers Pty Ltd

� Manly Council

� The Robinson Group

� Taylor Woodrow (Australia)

Pty Ltd

SSttaanndd AAlloonnee PPoowweerr SSuuppppllyy SSyysstteemmss

The Centre's expertise in

applied photovoltaics has been

effectively put to use by the

National Parks and Wildlife

Service (NPWS).

The success of the NPWS

Montague Island PV/diesel

hybrid system (with its subse-

quent reduction of fossil fuel

usage by 80%) has prompted

NPWS to install a 4 kW

PV/diesel hybrid system at

Green Cape on the far south

coast of NSW. This system was

commissioned in July 1999.

tender evaluation and thus

allowing NPWS to make an

informed decision.

Green Cape National Park has a

light house and two cottages. The

PV/diesel hybrid system supplies

power for up to 20 people.

As with Montague Island, in the

Green Cape project the PVSRC

was chosen for its non-partisan

expertise in renewable energy

systems. The DAD evaluated

the park's power requirements,

set tender specifications, con-

ducted a technical site visit for

tenderers, clarified the technical

content of the tenders during


� PV26

Design AssistanceDivision

Manager: Robert Largent

University Staff:

Dr Richard Corkish,


Project Staff: Nick Shaw

The Centre's Design Assistance

Division (DAD) has a primary func-

tion to make available the Centre's

photovoltaic and systems expertise

to University and off-campus indi-

viduals and groups.

comprises leading Australian energy

policy experts and provides analysis

and advice to governments and

planners on critical policy issues

impacting on renewables.

NNSSWW LLiicceennccee CCoommpplliiaanncceeAAddvviissoorryy BBooaarrdd ((LLCCAABB))

Professor Outhred continued

his appointment with the LCAB,

with 1999 activities concerned

with retailer progress in meeting

environmental targets and with

distributors meeting least cost

planning obligations.

The DAD handles public en-

quiries regarding the technical

issues concerning Photovoltaics

(PV) and its associated equipment

by offering information, advice

and commercial contacts. Advice

ranges from RAPS information,

equipment suppliers, and system

sizing to recommending the best

locations in gardens to install

solar powered lights.

Technical support for industry is

diverse, ranging from enquiries

concerning commercially avail-

able solar technology to institut-

ing full projects for the develop-

FIGURE PV31: A 4 KWP PHOTOVOLTAIC ARRAY INSTALLATION AT GREEN CAPE NATIONAL PARK.

FIGURE PV32: MEMBERS OF THE GROOVE DIFFUSION AFTER

PACKING THE HOUSE AT THE CAT AND FIDDLE IN BALMAIN:

(LEFT TO RIGHT) NICOLA HARTLEY, OLIVER NAST, ALEXANDER SLADE,

KEITH MCINOTSH, JEFF COTTER, NICK SHAW, NADIA HARTLEY,

RUNGE CUTTA, AND JOHNNY WU.

(ONLY ENGINEERS WOULD NAME A BAND AFTER

THEIR RESEARCH PROCESSES.)

Groove Diffusion Apart from their teaching and research activities, PhDstudents, friends and faculty from the PhotovoltaicsSpecial Research Centre have formed a rock and rollband called the Groove Diffusion. The band membersmeet regularly on Wednesday nights and often performtheir original works at house parties and local pubs.Feedback from the masses indicates that music loversaround the world will soon know of the GrooveDiffusion.


� T29


for

Third Generation Photovoltaics

Start-Up Report


for

Third Generation Photovoltaics

Start-Up Report

T3 �

SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE FFOORR TTHHIIRRDD GGEENNEERRAATTIIOONN PPHHOOTTOOVVOOLLTTAAIICCSS � SSTTAARRTT-UUPP RREEPPOORRTT

Table of ContentsTable of ContentsDirector’s Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T4

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T6

Efficiency Losses in Standard Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T8

Tandem Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T9

Multiple Electron-Hole Pairs Per Photon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T10

Hot Carrier Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T11

Multiband Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T12

Thermophotovoltaics and Thermophotonics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T13

Financials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T14

Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T15

T5 �


� T4

This success was undoubtedly aided

by the achievements of the Photo-

voltaics Special Research Centre,

whose maximum 9-year period of

ARC support terminated in

December, 1999. The new Centre

was one of a small number of such

Centres selected from applications

from around Australia across all

disciplines.

The Centre has activities clearly differ-

entiated from the Photovoltaics

Special Research Centre and the Key

Centre for Photovoltaic Engineering,

concentrating on a “third-generation”

of photovoltaic technology, not yet

fully conceived, let alone implement-

ed. I (Martin Green) will be the

Director of this new Centre with

Dr Armin Aberle, Deputy Director.

Dr Aberle will have special responsi-

bilities for the new Centre's experi-

mental programs.

Director’s ReportDirector’s Report

The new Centre will attempt to devel-

op ideas, able to be implemented in

thin-film form, likely to significantly,

rather than incrementally, improve

photovoltaic cell performance beyond

that of a single junction device.

Tandem stacks of solar cells of differ-

ing bandgaps are probably the best

known example of such a third-gen-

eration approach, whereby efficiency

can be increased merely by serially

stacking more cells. The new Centre

will explore approaches capable of

similar efficiency but using more

innovative “parallelled” approaches.

The following “start-up” report con-

tains more information on some of

the ideas to be explored and progress

made since the original application for

the new Centre was prepared. The

motivation for this initiative comes

from the premise that the manufac-

turing costs of mature products pro-

duced in increasingly large volume

eventually approach the costs of the

constituent materials.

This is already the case for “first-gen-

eration” wafer-based photovoltaics

where material costs (wafers, glass,

and encapsulants) account for over

70% of manufacturing cost. It will

eventually be the case for “second-

generation” thin-film technology

where the costs of glass or other

encapsulants will dominate. This

leaves efficiency as the key parameter

in determining the long term costs

and viability of photovoltaics.

Fortunately, there seems to be enor-

mous scope for improving photo-

voltaic energy conversion efficiency.

Most present day product is bounded

by a fundamental efficiency limit of

33%, struggling to attain half this

value in practice. However, the ther-

modynamic limit on the conversion of

sunlight to electricity is 93%. This

gives enormous scope for improve-

ment, provided

sufficiently innovative ideas can be

generated to take full advantage in the

progress in materials technology

expected over the next 20 years.

In the words of one reviewer of the applica-

tion for the new Centre: “The proposal

reminds me of the situations that existed

prior to other great semiconductor technology

inventions like the transistor and the integrat-

ed circuit. Both inventions came from perceived

requirements of the next generation of elec-

tronic devices in the marketplace. There were

no road maps when the groups began - just a

clear definition of the required result”.

I think this comment well

captures the excitement and potential

associated with the work of the new

Centre. I look forward to the challenge

of this potential to reality.

D I R E C T O R ’ S R E P O R T

PPrrooffeessssoorr MMaarrttiinn GGrreeeenn,,DDiirreeccttoorr,,SSppeecciiaall RReesseeaarrcchh CCeennttrree ffoorr TThhiirrdd GGeenneerraattiioonn PPhhoottoovvoollttaaiiccss

The University has been successful in its application for

an Australian Research Council (ARC) Special Research

Centre in Third Generation Photovoltaics, which

commenced in January, 2000.

SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE FFOORR TTHHIIRRDD GGEENNEERRAATTIIOONN PPHHOOTTOOVVOOLLTTAAIICCSS � SSTTAARRTT-UUPP RREEPPOORRTT I N T R O D U C T I O N

T7 �� T6

in series. In this case, the cell stack

operates essentially as a two termi-

nal device, as for a standard cell.

Such “monolithic” tandem

cells, involving up

to three different

bandgap cells

a r e

now in

p r o d u c t i o n

for spacecraft, with

energy conversion effi-

ciency up to 30%. They are

also used to improve stability in amor-

phous silicon solar cells, where the best

commercial triple junction modules

have more modest efficiencies in the

6-7% range.

High efficiency is possible, in princi-

ple, merely by increasing the number

of cells in the stack. In practice, not

only does this increase complexity, it

increases sensitivity to spectral varia-

tions in sunlight, unless separate con-

nections to each cell are made.

Although the tandem cell approach is

important in demonstrating the

feasibility of “third-generation”

approaches giving efficiencies close to

thermodynamic limits, it will not be

the focus of efforts of the new

Centre. The new Centre will seek

to investigate and develop approaches

of a more “parallel” nature than

the “serial” nature of the tandem

approach.

“Hot carrier” cells provide an example

of such an integrated, “parallel”

approach. One of the main loss

mechanisms in a conventional solar

cell is the thermalization of photo-

excited carriers with the atoms in the

crystal lattice. The tandem approach

reduces the magnitude of this loss. A

options discussed in the following sec-

tions and for related “proof-of-con-

cept” experimental work. The objec-

tive is, within nine years, to have

developed one or more of the most

promising options to the stage where

it can be commercially evaluated.

Figure T3 diagramatically shows the

advantages that may be expected by

the successful implementation of a

thin-film third-generation approach

compared to both first- and

second-generation approaches. First-

“hot carrier”

cell seeks to

avoid this

loss by re-

stricting energy

loss by phonon emis-

sion in the cell. Very little

prior theoretical or experimen-

tal work has been done in this area.

The increased flexibility offered by the

emerging field of low-dimensional

semiconductors would seem to have

considerable potential here. Of partic-

ular interest are prospects for

IntroductionIntroduction

approach limits the potential for

cost reduction and hence the possi-

ble long-term impact of the tech-

nology. It seems likely that a mature

thin film approach will displace first-

generation technology over the next

10 years.

Since the energy conversion efficien-

cy of any such second-

generation technolo-

gy is unlikely to

reach even

that of

t h e

first-genera-

tion (15%), this leaves

improved thin-film energy conver-

sion efficiency as the area of

highest impact for future

research. There would seem to be

enormous scope for improve-

ment given that the thermody-

namic limit upon the efficiency of

conversion of sunlight to electric-

ity is 93%, although the route to

such high efficiency is at present

unclear. The development of

concepts and supporting technol-

ogy for a high efficiency “third-

generation” photovoltaic technol-

ogy based on thin films is the pri-

mary aim for the new Centre for

Third Generation Photovoltaics.

Director:


Deputy Director:

Dr Armin Aberle

Co-Applicants:

Dr Pietro Altermatt

Mr Andrew Brown

Dr Patrick Campbell

Dr Richard Corkish

Dr Mark Gross

Dr Mark Keevers

Dr Aihua Wang

With the acceptance of the grow-

ing importance of sustainable

energy generation technologies,

photovoltaics is clearly an

important industry for a

research focus within

Australia. Not only

does such

research have to

address the short to medium

term concerns of the local indus-

try but, for the industry to retain

its leadership role, the research

also has to remain at the forefront

in investigating future options, so

that the most relevant of these are

identified early and the appropriate

investments made.

In the past, the research work

likely to make the largest impact

upon the industry has been that

allowing a transition from first-

generation silicon wafer-based

technology (Figure T1), to that of

thin films supported on a foreign

substrate, such as the polycrys-

talline silicon film on glass exam-

ple of Figure T2 (“second-gener-

ation” technology). The material

intensiveness of the wafer-based

The limiting efficiency of 93% is

slightly lower than the Carnot effi-

ciency of 95% (based on a tempera-

ture of 6000 K for the sun's photo-

sphere, and a 300 K terrestrial tem-

perature). This is because the latter

is based on the net energy transfer

between the sun and the cell. The

lower figure is more pragmatic in

regarding the energy radiated by the

cell back to the sun as a loss.

In the past, several photovoltaic

approaches have been shown, in

principle, to be capable of perform-

ance quite close to this limit.

One, based on multi-

ple or tandem cells, is

quite well developed and

understood. By splitting

the solar spectrum into nar-

row wavelength bands and convert-

ing these in separate cells of appro-

priate energy bandgap, energy con-

version efficiency can be increased.

In the limit of an infinite number of

cells, the limiting conversion efficien-

cy for direct sunlight is 86.8%. An

elegant development of this

approach is to have the cells stacked

in order of decreasing bandgap. The

uppermost wide bandgap cell will

absorb the high energy photons it is

able to convert, passing photons of

energy below its bandgap through to

the underlying cell, where the process

continues. A further simplification

occurs, in practice, if each cell con-

verts the same number of photons,

so that their output currents are

matched and they can be connected

FIGURE T2: AN EXAMPLE OF “SECOND-GENERATION”

THIN-FILM TECHNOLOGY (MODULE FABRICATED ON

PACIFIC SOLAR'S SYDNEY PILOT LINE DURING 1998,

BASED ON THIN-FILMS OF POLYCRYSTALLINE SILICON

ON GLASS, AGAIN UNSW-DEVELOPED TECHNOLOGY).

FIGURE T1: “FIRST-GENERATION”

WAFER-BASED TECHNOLOGY (BP

SOLAREX SATURN MODULE, THE

PHOTOVOLTAIC PRODUCT MANU-

FACTURED IN THE HIGHEST VOL-

UME BY THE COMPANY IN EUROPE

DURING 1999, USING UNSW

BURIED CONTACT TECHNOLOGY).

Australia is already a key player in photovoltaics (solar elec-

tricity) as the largest manufacturer per capita, a research

leader, and the developer of the current industry-leading

“buried contact” cell technology.

FIGURE T3: EFFICIENCY AND COST PROJECTIONS FOR FIRST-, SECOND- AND

THIRD-GENERATION PHOTOVOLTAIC TECHNOLOGY (WAFERS, THIN-FILMS,

AND ADVANCED THIN-FILMS, RESPECTIVELY).

“phononic” engineering to allow “hot

carrier” populations to be maintained

and the design of contacts to allow the

required “isoentropic cooling” of

these populations. Energy conversion

efficiency essentially equal to the infi-

nite tandem cell case is obtainable, in

principle, if these issues can be satis-

factorily addressed.

The new Centre aims to become an

international focal point for efforts to

explore a range of such “parallelled”

generation technology, due to its

material intensiveness, is unlikely to

attain manufacturing costs below

US$150/m2 or US$1/Watt. Second-

generation thin film technology may

ultimately reach costs of US$30/m2

or below US$0.50/Watt. Although

third-generation may not reach the

same low costs per unit area as

second-generation technology, the

resulting high efficiency could

result in very low costs below

US$0.20/Watt.

Tandem Cells

T9 �


� T8

Efficiency Losses in Standard CellsEfficiency Losses in Standard Cells

tion can be used to derive quite funda-

mental limits on achievable solar cell

performance. This approach revisits

“black body” radiation, the topic that

stimulated the birth of quantum

mechanics during investigations by

Max Planck in 1900.

Basically, radiation from the sun

approximates that from a “black body”

held at a warm 6,000 K, the tempera-

ture of the sun's photosphere (a black

body is just a perfect absorber and

hence emitter of light). The energy dis-

tribution of this radiation is described

by a formula developed by Planck. In

Shockley and Queisser's approach, the

solar cell is also modelled by a black

body, but at the more typical terrestrial

temperature of 300 K. They realized

that Planck's formula would need to be

modified for a device where the light

was generated by recombination

between electrons and holes at differ-

ent potentials in the conduction and

valence band. In fact, the emitted radi-

ation increases more than exponential-

ly as the voltage across the cell increas-

es for photon energies above the

bandgap. This is well known qualita-

tively from light emitting diodes and

the semiconductor laser areas.

When open-circuited, the voltage of

the ideal cell builds up so that the num-

ber of above bandgap photons emit-

ted as part of this voltage - enhanced

radiation balances those in the incom-

ing sunlight. At voltages below open-

circuit, the number of emitted photons

is less, the difference between incom-

ing and outgoing being due to elec-

trons flowing through cell terminals.

In this way, Shockley and Queisser

were able to show that the perform-

A key fundamental loss process is

process 1, whereby the photoexcited

electron-hole pair quickly loses any

energy it may have in excess of the

bandgap. A low energy red photon is

just as effective in terms of outcomes

as a much higher energy blue photon.

This loss process alone limits conver-

sion efficiency of a cell to about 44%.

Another important loss process is

process 2, recombination of the pho-

toexcited electron-hole pairs. This can

be kept to a minimum by using semi-

conductor material with appropriate

properties - especially high lifetimes

for the photogenerated carriers.

This can be ensured by eliminating all

unnecessary defects. The lifetime

is then determined by radiative

recombination processes in the cell,

the inverse process to the photoexcita-

tion process.

As shown in 1960 by William Shockley

and Hans Queisser, this symmetry

between light absorption and light

emission during radiative recombina-

ance of a standard cell was limited to

31.0% efficiency for an optimal cell

with a bandgap of 1.3 eV (electron

volts). This is lower than the

figure of 44% previously mentioned

since the output voltage of the cell is

less than the bandgap potential, with

the difference made up by the voltage

drops at the contact and junction.

These drops can be reduced if the

sunlight is focussed to increase the

photon density striking the cell. Under

the maximum possible sunlight con-

centration (46,200 times!), the limiting

efficiency increases to 40.8%. How-

ever, only the direct component of

sunlight can be focussed in this way.

This is not an issue when above the

earth's atmosphere. However, sunlight

is scattered by this atmosphere so that

only about 75% of the light reaching

the earth's surface is direct. Only this

component can be converted with this

efficiency, even in principle.

However, as the figure under maximal

concentration gives the highest numer-

ical value, this direct light conversion

efficiency is a useful figure and is use-

ful in comparing the ultimate efficien-

cy potential of any given approach.

This efficiency is also more directly

comparable with the results from clas-

sical thermodynamics.

For example, the conversion

efficiency of energy from a source at

6,000 K with a sink temperature of

300 K is limited by the Carnot effi-

ciency (1 - Tsink/Tsource) to 95.0%.

However, this value does not count the

photons emitted by the cell as a waste,

since it assumes they get back to the

sun, helping it to maintain its tempera-

ture! A limit that regards these pho-

tons as a loss while assuming the

process is reversible, as in the

Carnot limit, is 93.1%. Some of the

schemes to be investigated in the new

Centre can approach this limit

reasonably closely.

FIGURE T4: LOSS PROCESSES

IN A STANDARD SOLAR CELL:

(1) THERMALISATION LOSS;

(2) AND (3) JUNCTION AND

CONTACT VOLTAGE LOSS; (4)

RECOMBINATION LOSS.

Loss processes in a standard single junction cell are indi-

cated in Figure T4, which shows the energy of electrons

in the cell as a function of position across it. Photons in

sunlight excite electrons from the valence band across

the forbidden gap to the conduction band.

Tandem Cells

tively. Having to independently oper-

ate each cell is a complication best

avoided. Usually cells are designed so

that their current outputs match so

that they can be connected in series.

Fortunately, just stacking the

cells with the highest bandgap

cell uppermost as shown in

Figure T5 automatically achieves

the desired filtering. Perfor-

mance increases as the number

of cells in the stack increases,

with a direct sunlight conversion

efficiency of 86.8% calculated

for an infinite stack of independ-

ently operated cells. For such a

large number of cells, each

would operate as a Geiger count-

er, each patiently waiting for a

photon of the correct energy to

get through the filter.

Fortunately, the performance is

quite good even with a relatively

small number of cells in the

stack, increasing from the single

cell value of 40.8% to 55.9%,

63.8% and 68.8% as the number

of independently operated cells

increases to 2, 3 and 4, respec-

Tandem cells are already in com-

mercial production for two distinct-

ly different technologies. Double

and triple junction cells based on

the GaInP/GaAs/Ge system have

been developed for use on space-

craft with terrestrial sunlight con-

version efficiencies approaching

30%. Quadruple junction devices

with efficiencies approaching 40%

are presently under development

for such use. Tandem cells are also

used to improve the performance

and reliability of terrestrial amor-

FIGURE T5: AN ALL-SILICON

TANDEM CELL CONCEPT BASED

ON SI/SIO2 SUPERLATTICES.

The key loss process 4 of Figure T4 can be largely eliminat-

ed if the energy of the absorbed photon is just a little higher

than the bandgap of the cell material. This leads to the con-

cept of the tandem cell, where multiple cells are used with

different bandgaps, each converting a narrow range of

photon energies close to its bandgap.

FIGURE T6: AN ALL-SILICON TANDEM CELL CONCEPT

BASED ON SI/SIO2 SUPERLATTICES

This additional constraint slightly

reduces achievable performance.

More importantly it makes the design

very sensitive to the spectral content

of the incident sunlight. Once the

output current of one cell in a series

connection drops more than about

5% below that of the next worst cell,

the best that can be done for overall

performance is to short-circuit the

low output cell, otherwise it will con-

sume, rather than generate power. A

by-pass diode that limits this

consumed power is the most practical

way of implementing this short-

circuit to date. Some of the other

high efficiency approaches discussed

below do not suffer from this spectral

sensitivity.

phous silicon cells with stabilised

efficiencies up to 12% confirmed

for triple junction cells based on the

Si:Ge:H alloy system. Modules with

efficiencies in the 6-7% range are

available incorporating double and

triple junction devices.

Since this technology is well

understood and developed,

Centre programs will focus on

alternatives discussed below.

However, one area of interest

will be the use of Si/SiO2 super-

lattices potentially to allow sili-

con's bandgap to be controlled.

Such control would make an all-

silicon tandem cell as shown in

Figure T6 feasible.

E F F I C I E N C Y L O S S E S

T A N D E M C E L L S

Multiple Electron-Hole Pairs Per Photon

T11 �


� T10

Multiple Electron-Hole Pairs Per Photon

Raman scattering of high energy

photons. Raman scattering is a gener-

ic term applied to the inelastic scat-

tering of photons (scattering

processes that result in a change in

photon energy also, usually, in direc-

tion). In the semiconductor field,

Raman scattering by light interaction

with lattice vibrations (phonons) is

well known, and forms the basis of a

well known characterisation

approach. Formally, the scattering

process involves the creation of a

“virtual” electron-hole pair by the

photon in a process that conserves

momentum but not necessarily ener-

gy. The virtual pair remains viable for

Evidence for the creation of more

than one electron-hole pair by high

energy photons has been document-

ed since the 1960's for Si and Ge,

usually attributed to impact ioniza-

tion by the photoexcited carriers.

More recently, the limiting efficiency

possible for an idealized cell capable

of taking full advantage of this

impact ionization effect has been rig-

orously analysed. A limiting efficien-

cy of 85.4% has been calculated for a

cell of bandgap approaching zero,

allowing, on energy grounds at least,

many electron-hole pairs to be gener-

ated by each incident photon.

In reality, the measured effect in any

material to date is so weak so as to be

able to produce negligible improve-

ment in device performance. In

experimental devices, competitive

processes for the relaxation of the

high energy photoexcited carriers are

too efficient.

One aspect that the Centre will be in

a good position to explore is the via-

bility of improving the relative effec-

tiveness of the impact ionization

process. For example, alloying Ge

with Si in the surface region of a cell,

where high energy photons are

absorbed, will change the relative

dynamics, possibly for the better.

Similarly, incorporation of a Si/SiO2

superlattice in this region, of interest

on other grounds, will similarly have

an impact on these dynamics.

Preliminary work is already underway

in the former area.

The Centre also plans to conduct

more innovative work based on the

the virtual pair interacts. (A very sim-

ilar process explains the high

refractive index characteristic of

semiconductors. The virtual pair,

in the more general case, relaxes

elastically, by emitting a photon of

the same energy as the original

one, in the original direction. This

process slows the propagation of

light compared to that in vacuum

by a factor equal to the magnitude

of the refractive index).

Rather than the standard Raman

process, the Centre will investigate

the feasibility of enhancing a related

Raman scattering process that

involves the virtual pair relaxing to

other states in their respective bands

during the second stage of the

process involving, in this case, pho-

ton emission. The net result would

then be that a photon was absorbed

in creating an electron-hole pair, with

a second photon emitted of energy

up to that of the surplus energy of

the first photon above the bandgap.

One way of enhancing such effects

would be to use semiconductor

material with only a finite band of

allowed states in both conduction

and valence bands (Figure T7). This

would remove competitive processes

for the absorption of high energy

photons, promoting virtual absorp-

tion processes.

An analysis of the efficiency of

cells based on such Raman scatter-

ing shows that they are con-

strained by identical bounds to

those on cells based on impact

ionisation. In principle, 85.4%

efficiency is possible from such

cells. The difference between the

approaches may prove to be dif-

ferences in the practicality of

implementation.

If, instead of giving up their energy as heat loss, the high

energy electron-hole pair instead use their excess ener-

gy to create additional electron-hole pairs, higher

efficiency would be possible in principle.

FIGURE T7: PHOTOVOLTAIC

DEVICE BASED ON RAMAN

LUMINESCENCE

a finite time determined by the ener-

gy imbalance. During this period, for

Raman phonon scattering, the virtual

pair relaxes emitting a photon of an

energy that differs from that of the

original photon by the energy of the

lattice vibration (phonon) with which

The various time constants involvedcan be appreciated by imagining adirect bandgap cell illuminated by ashort pulse of monochromatic laserlight. Such a pulse creates electrons inthe conduction band and holes in thevalence band of very distinct energyand momentum as in Figure T9.Collisions of these photoexcited carri-ers occur in less than a picosecond,tending to smear out this distribution.Similar collisions were studied byLudwig Boltzmann, in his study ofcollisions between gas molecules, inthe 1800s. He showed that moleculesevolve towards a distribution in energywith an exponentially decaying tailwith a characteristic decay constantequal to the “thermal energy”, kT.

Electrons behave similarly, apart fromslight departures near the band edgesince they are fermions. After a num-ber of collisions, the initially peakeddistributions becomes broader andtends towards the type of distributionderived by Boltzmann. If carriers col-lide elastically only with carriers of thesame type, no energy is lost from thisgroup of carriers. The temperature ofthe “hot carrier” distribution is deter-mined by the total number of carrierscreated by the laser pulse and the totalenergy given to each carrier type.Different temperatures are possiblefor electrons and holes unless efficientat sharing energy.

In the next phase, collisions with thelattice atoms become important.These result in energy loss to lattice(phonon emission). During this phase,the number of electrons and the num-ber of holes remain constant (neglect-ing impact ionization), but the average

before they get too far into the recom-bination stage of this decay sequence.A hot carrier cell has to catch thembefore the carrier cooling stage.Carriers either have to traverse the cellquickly or cooling rates have to beslowed. Special contact designs to pre-vent contacts from cooling the carriersmay also be required.

Apart from two theoretical studiesand experiments showing reducedcooling rates in semiconductorsuperlattices, little prior work hasbeen undertaken on hot carriercells. The Centre seeks to developspecific cell designs paying partic-ular attention to contact design.Work to date at the Centre showsthat the limiting efficiency of thisapproach is intermediate betweenthe 85.4% and 86.8% values ofthe two previous sections.

FIGURE T9: ENERGY RELAXATION OF CARRIERS AFTER A

SHORT, HIGH-INTENSITY LASER PULSE AT t = 0.

When photoexcited carriers collide elastically with one another,

no energy is lost. It is inelastic collisions with the atoms of the cell

material that result in an energy loss (through phonon emission).

In principle, if such atomic collisions can be avoided during the time

it takes a photogenerated carrier to traverse the cell, the energy

loss associated with process 1, of Figure T4 can be avoided.

FIGURE T8: HOT CARRIER CELL CONCEPT.

CARIERS STAY HOT, WHILE THE CELL STAYS COOL.

energy and carrier temperaturedecrease. The temperature of elec-trons and holes equalise and bothreduce towards the temperature of thehost material.

Finally, recombination in the semicon-ductor becomes important. The distri-butions of electrons and holes retainthe same general shape, determined bythe ambient temperature, but thenumber of carriers at each energyreduces until finally reaching the levelsprior to the laser pulse. A standard cellis designed to collect the carriers

Hot Carrier CellsHot Carrier Cells

M U L T I P L E E L E C T R O N - H O L E

H O T C A R R I E R C E L L S

T13 �


� T12

Multiband CellsMultiband Cells

more tolerant to spectral varia-

tions in sunlight than the series

tandem case.

Centre work has also already

resolved an issue that has been

controversial within the photo-

In recent Centre work, this the-

ory has been extended to an n-

band cell and some possible

implementation approaches dis-

cussed. These include excita-

tions between minibands in

semiconductor superlattices, if

phonon relaxation processes can

be controlled, the use of semi-

conductors with multiple nar-

row valence and conduction

bands, such as I-VII and I3-VI

compounds or the use of high

concentrations of impurities

such as rare-earth elements to

form multiple impurity bands in

wide bandgap semiconductors.

The limiting efficiency for an n-

band cell has been shown to be

identical to the 86.8% figure for

a large stack of tandem cells.

However, the effective cell con-

nections in the n-band approach

show much more redundancy

than in a series connected

tandem cell (Figure 10). This

suggests the approach may be

voltaic community. This is

whether an idealised cell incor-

porating multiple quantum wells

can exceed the efficiency of an

idealised standard cell. By sug-

gesting the structure of Figure

T12, which shows a multiple

quantum well cell that meets all

the requirements, in principle,

need to attain the limiting 3-

band cell performance, the

question is now answerable in

the affirmative.

FIGURE T10:

THREE BAND SOLAR CELL.

FIGURE T11: FOUR BAND CELL AND EQUIVALENT CIRCUIT.

FIGURE T12: MULTIPLE QUANTUM WELL SOLAR CELL

MEETING THE CONSTRAINTS OF 3-BAND THEORY.

Standard cells rely on excitations between the valence and

conduction band of a semiconductor. A recent analysis has

shown efficiency advantages if a third band, nominally an

impurity band, is included in the analysis (Figure T10).

Thermophotovoltaics & ThermophotonicsThermophotovoltaics & Thermophotonics

Basically, the heated device acts

as an emitter of narrow band-

width light within an energy, kT,

of its bandgap energy. This near-

monochromatic light can be con-

verted very efficiently by the cell.

Moreover, light emitted by the

cell is recycled back to help drive

the light emitting diode.

Additionally, since the voltage

This source may be an element

heated to high temperature, such

as by using a gas burner. High

efficiency is possible in this case

for two reasons. One is that the

light source may emit a narrower

bandwidth of light than the sun,

such as the case when heated

ceramics containing rare-earth

elements are used as the source.

A second reason is that energy

from the cell, such as that

reflected or emitted as light, can

be recycled to the source increas-

ing overall efficiency.

In the original Centre applica-

tion, a development of this

approach dubbed “thermopho-

tonics” was described and has

since been the subject of a

Centre patent application. In this

case, the exponentially enhanced

light output of a device where

the light is generated by recom-

bination between carriers in a

conduction and valence band, as

described earlier, is used to

advantage.

Figure T13 shows the basic

arrangement which is nearly sym-

metrical. Two idealised diodes act-

ing as solar cells/light emitters

face each other and are connected

by a load. Heat is supplied to one

to heat it hotter than the other and

heat is extracted from the other to

maintain it at a cooler temperature.

The devices are optically coupled

but thermally isolated. The combi-

nation is able to convert heat sup-

plied to the hotter device to elec-

tricity in the load with an efficien-

cy approaching the Carnot effi-

ciency, in principle.

results in power dissipation in the

load. If a non-absorbing, narrow

band fitter is placed between the

cell and diode, the efficiency of

conversion of heat supplied to the

diode to electrical power in the load

can approach the Carnot efficiency.

The efficiency is lower without this

filter due to the thermal smearing

represented by the effective kT

energy bandwidth.

With on-going evolution in device

design, both experimental solar

FIGURE T13: THERMOPHOTONIC CONVERSION.

Thermophotovoltaics is a well-established branch of

photovoltaics where a light from a heated body other

than the sun is used as the illuminating source

across this diode, which determines

the energy of the incoming elec-

trons, is less than its bandgap

potential, which determines the

energy in the emitted photons, the

diode has to be heated to maintain

its temperature if operating at high

quantum efficiency due to the con-

sequent refrigerating action associ-

ated with this energy gain.

Since the same current flows in the

cell and source diode, the voltage

across the diode will be smaller than

that across the cell when the diode

is at higher temperature. This

cells and light emitting diodes are

approaching the stage where inter-

nal recombination is limited by

radiative processes, a prerequisite

for the success of this scheme. If

used to convert solar radiation in

conjunction with a thermal

absorber, energy conversion

efficiency up to 85.4% is obtainable

in principle. Alternatively, the

approach could be used for maxi-

mally efficient conversion of fossil

fuels or waste heat. It may prove

ideal for the latter when the heat is

available at low temperature.

M U L T I P L E B A N D C E L L S

T H E R M O P H O T O V O L T A I C S

Centre Director, Professor Martin

Green, presented an invited keynote

paper outlining some of the ideas the

Centre would be working on at the

The Third International Conference

on Low Dimensional Structures and

Devices in September, 1999 at

Antalya, Turkey. He is also scheduled

to give a paper on the same topic at

the 16th European Photovoltaic Solar

Energy Conference, Glasgow in May

and an invited paper at the 8th

International Symposium on Nano-

structures: Physics and Technology in

St. Petersburg in June. Provisional

patent specifications have been filed,

or prepared for filing, on some of the

ideas believed innovative relating to

multiband cells, thermophotonic con-

version, and Raman luminescence. A

number of journal papers have either

been submitted for publication or are

awaiting review, pending patent filing,

as indicated below.

Journal PublicationsM.A. Green, “Potential for Low

Dimensional Structures in Photo-

voltaics”, Materials Science and

Engineering B, (in press).

ConferencePublicationsM.A. Green, “Potential for Low

Dimensional Structures in Photo-

voltaics”, Conference, The Third

International Conference on Low

Dimensional Structures and Devices,

Antalya, Turkey, September, 1999.

M.A. Green, “Third Generation

Photovoltaics: Advanced Structures

Capable of High Efficiency at Low

Cost”, 16th European Photovoltaic

Solar Energy Conference, Glasgow,

May, 2000, to be published.

M.A. Green, “Prospects for

Photovoltaic Efficiency Enhance-

ment Using Low Dimensional

Structures”, 8th International Sym-

posium on Nanostructures: Physics

and Technology, St. Petersburg, June,

2000, to be published.

Green, M.A., “Multiple Band

Luminescent Photovoltaic Con-

verters: General Theory and

Comparison to the Tandem Solar

Cell Approach”, (in press).

Green, M.A., “Third Generation

Photovoltaics: Ultra-High Efficiency

at Low Cost”, (in press).

Green, M.A. and Wenham, S.R.,

“Thermophotonic Conversion: A

New Conversion Concept for Low

Grade Heat”, (in press).

Green, M.A., “Potentially High

Efficiency Solar Cells Based on

Raman Luminescence”, (in press).

Green, M.A., “Limiting Mono-

chromatic Photovoltaic Conversion

Efficiency”, awaiting review.

Green, M.A., “Fermi-Dirac, Bose-

Einstein and Related Integrals and

their Inverses for Negative Argu-

ments”, prepared for publication.

SSPPEECCIIAALL RREESSEEAARRCCHH CCEENNTTRREE FFOORR TTHHIIRRDD GGEENNEERRAATTIIOONN PPHHOOTTOOVVOOLLTTAAIICCSS � SSTTAARRTT-UUPP

� T14

FinancialsFinancialsResearch and Development Fund.

The Centre has also been advised

that its application for an interna-

tional grant under the Japanese

Research Institute of Innovative

Technology for the Earth (RITE)

Research Proposal Competition

has been successful.

The above funds will be used to

maintain and develop laboratory

The initial Australian Research

Council grant is $1,540,000 over

the 2000-2002 triennium. These

funds are being augmented by an

Australian Research Fellowship

and considerable support from the

University of New South Wales.

Additional funding of up to

$218,540 over the same period has

been awarded under the New

South Wales Sustainable Energy

facilities for this work, for the sup-

port of postgraduate students,

postdoctoral researchers and visit-

ing academics wishing to become

involved in this research, and for

the support of collaborative

research with local and overseas

institutions, such as by hosting

workshops and participating in

staff exchange.

PublicationsPublications

1999

Key Centre

for

Photovoltaic

Engineering

UUNNSSWW

1999

Key Centre

for

Photovoltaic

Engineering

UUNNSSWW


Key Centre for Photovoltaic Engineering

Electrical Engineering Building


UNSW SYDNEY NSW 2052

AUSTRALIA

Tel+61 2 9385 4018 Fax+61 2 9662 4240

E-mail: [email protected] http://www.pv.unsw.edu.au

Annual Report

1 KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG D I R E C T O R ’ S R E P O R T

K3 �� K2

The University of New South

Wales's (UNSW) commitment to

provide the Key Centre with access

to income earned, such as through

EFTSUs and research quantum, has

been achieved through the establish-

ment of the Centre for Photovoltaic

Engineering. This Centre conforms

to the standard school structure

adopted throughout UNSW and

therefore becomes an "umbrella"

Centre encompassing all the photo-

voltaic and related activities such as

its Key Centre and two Special

Research Centres. However,

UNSW’s commitment to establish

the Centre for Photovoltaic

Engineering as an independent

budget unit or autonomous centre,

is dependent upon the demonstra-

tion of sustainability. A decision on

this issue will not be made prior to

the three yearly review of the Key

Centre. Nevertheless, with the sup-

port of the Dean of Engineering,

the Centre for Photovoltaic Engin-

eering from a financial perspective,

is being treated as if it were an inde-

pendent budget unit with an income

allocation directly from the Faculty.

The first year of operation has

therefore been a challenging transi-

tion year due to the complicated

process of establishing this financial

independence.

In the educational area, the pri-

mary new initiative of the Key

Centre has been the development

and establishment of the new

Bachelor of Engineering in

Photovoltaics and Solar Energy.

Following extensive curricula

development, approval for the new

program was granted at School,

Faculty, Academic Board and

University Council levels. UAC list-

ing for the new Bachelor of

Engineering was achieved in 1999,

with first enrolments taking place

in the year 2000. The performance

measure target of enrolling 25-35

students in the year 2000 was com-

fortably achieved with 41 new stu-

dents officially enrolling in the first

year of the program. Importantly

the new program, even though in

its infancy, has demonstrated its

ability to attract the highest quality

students as discussed later in the

reports. Another aim of the Key

Centre has been to attract new

PhD enrolments, primarily

through attracting new top quality

staff capable of carrying out the

corresponding supervision. To this

extent, the Key Centre has been

extremely fortunate to attract two

new academic staff members, Dr

Armin Aberle and Dr Jeff Cotter

who in combination have taken on

in Australia. The successful collabo-

ration with Eurosolare has led to a

new license agreement and corre-

sponding technology transfer in

recent months. In the educational

area, one of the more important col-

laborations has been with the

Australian CRC for Renewable

Energy (ACRE). This new collabora-

tion commenced in April 2000 and

involves provision of funding from

ACRE to the Key Centre to support

educational activities in the areas of

distance learning via the Internet,

school programs and community

education. A memorandum of

understanding is also currently being

negotiated to establish educational

collaboration with the other three

institutions with strong interests in

photovoltaics and renewable energy,

namely Murdoch University, Curtin

University and the Australian

National University.

Many of the Key Centre’s achieve-

ments and activities have been pub-

lished through international confer-

ences, journals, media interviews,

newspaper and magazine articles,

and trade journal publications.

Considerable emphasis has been

placed on the promotion of the Key

Centre and its activities, particularly

with regard to disseminating infor-

mation about the new Bachelor of

Engineering in Photovoltaics and

Solar Energy. Another avenue for

information dissemination has been

through the fortnightly seminar pro-

gram run jointly between the Key

Centre for Photovoltaic Engineering

and the School of Electrical

Engineering under the direction of

Associate Professor Hugh Outhred.

In summary, the Key Centre for

Photovoltaic Engineering has

achieved all the outcomes expected

for the first year of operation, in

both teaching and research.

The activity plan and projected

expenditure for the next twelve

months remain as indicated in the

original Key Centre proposal. In par-

ticular, the development of the new

Master of Engineering Science in

7 post-graduate research students

since the commencement of the

Key Centre.

A necessary outcome for the Key

Centre has been the implementation

of its proposed management struc-

ture, the effectiveness of which is

best assessed through evaluation of

the effectiveness of the Key Centre

activities. The management commit-

tee meets fortnightly with the only

significant change to the manage-

ment structure originally proposed

being the direct reporting of the col-

laborative research program man-

agers to the Centre director.

In the areas of links and national

focus, the Key Centre has been quite

effective at establishing new collabo-

rations with industry related organi-

sations, manufacturers and other

institutions. In the area of industry

funded collaborative research, the

Key Centre has successfully negotiat-

ed a collaborative program with each

of the Australian photovoltaic manu-

facturers, BP Solar, Pacific Solar and

Solarex. The most recent of these to

be negotiated has been with Solarex,

with the project due for commence-

ment in 2001. Another company,

Eurosolare from Italy, has expressed

an interest in possible manufacturing

Director’s ReportDirector’s Report

PROFESSOR STUART R. WENHAM,

DIRECTOR, KEY CENTRE FOR PHOTOVOLTAIC ENGINEERING

THE SOLAR ENERGY REACHING THE EARTH’S SURFACE IN

ONE DAY EXCEEDS MANKIND’S TOTAL ENERGY REQUIREMENTS

FOR THIRTY YEARS.

The first year of operation has been a challenging but exciting

period for the Key Centre with the industry booming and

excellent progress made against many of the performance

measures and expected outcomes. Perhaps of greatest impor-

tance has been the granting of financial independence from the

School of Electrical Engineering.

This honours the University's commitment towards the

longer-term establishment of an autonomous centre. This has

been an essential precursor to the Key Centre demonstrating

its longer term sustainability, one of the most important crite-

ria against which the Key Centre will be judged.

Photovoltaic Engineering and the

development of a range of double

degree programs at undergraduate

level, will complement the ongoing

development of the new Bachelor of

Engineering.

KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG I N T R O D U C T I O N

K5 �� K4

An important aim of each Key

Centre is to become a national

focus in it's particular area. For the


Engineering, this has encouraged

the establishment of collaborative

programs with other institutions,

organizations and industry. Collab-

orations have also been established

with overseas institutions and

organizations, although in general

these have been initiated by over-

seas organizations wanting to

benefit from Key Centre educa-

tional programs, expertise and/or

technology.

In the research area, all programs

have been industry initiated and

self-funding. It was made clear

when establishing the Key Centre

for Photovoltaic Engineering that

it's ARC funds would not be used

to fund research projects.

Nevertheless, the Key Centre has

successfully established several

industry collaborative research

programs funded by the industry

partner and in a couple of cases,

through ARC SPIRT grants.

The primary new initiatives of

this new Key Centre are in the

educational area. In particular, the

Key Centre is developing the

world’s first Bachelor of Engin-

eering in Photovoltaics and Solar

Energy. This is in response to

rapid growth in the industry in

recent years in excess of 30% per

annum, with the expectation that

this rate of growth will continue

for many years to come. As

expected, substantial levels of job

creation, particularly for appro-

priately trained engineers, are tak-

ing place throughout the renew-

able energy sector as a whole and

in particular within the photo-

voltaics industry. There appears

to be a very important future for

photovoltaic engineering.

Growth inPhotovoltaic andRenewable EnergyEngineering

WWhhaatt iiss PPhhoottoovvoollttaaiicc ((PPVV))EEnnggiinneeeerriinngg??

Photovoltaic Engineering focuses

on the manufacture and use of

photovoltaic modules and the

implementation of photovoltaic

one million houses for America.

Governments have demonstrated

their willingness to offer whatever

subsidies are necessary to ensure

these targets are met, particularly

in Europe and Japan.

In response to the booming PV

market, many manufacturers glob-

ally are rapidly increasing their

production capacity. Australian

manufacturers currently enjoy

almost 8% of the international

market, a figure that is expected to

increase in the future as state of

the art Australian technology

enters the market place. The

explosive demand for photo-

voltaics causes dramatic drops in

the cost of PV, which in turn pro-

motes additional growth. Figure

K3 shows historically the relation-

ship between the cost of photo-

voltaic modules and the corre-

sponding installed capacity or

market size. If this straight line

relationship continues as expect-

ed, then the reduction of the pho-

tovoltaic module price to its

apparent long term potential of

under $1 per Watt, could lead to

photovoltaic markets expanding

by more than a factor of 1,000.

International studies predict an

expansion of more than a factor

of 20 over the coming decade.

results of a study that predicted

30,000-80,000 new jobs would be

created in Austria alone in the pho-

tovoltaic sector by 2010. Similar

types of studies have been carried

out throughout the world, with

similar types of conclusions drawn

with regard to job creation. Using

data from these studies, Figure K4

shows that the likely international

job creation in the photovoltaics

sector by the year 2004, when the

first photovoltaic engineers gradu-

ate from UNSW, is about 50,000-

60,000 new jobs. Many of these

will be engineering positions.

JJoobb CCrreeaattiioonn aanndd EEdduuccaattiioonnaallRReeqquuiirreemmeennttss

The rapidly expanding photo-

voltaic industry creates the need

for photovoltaic engineers. Inter-

national studies indicate that

approximately 50 new jobs are

created for each 1 MW per annum

increase in production capacity of

photovoltaics. Based on present

growth rates in the industry, this

indicates that hundreds of thou-

sands of jobs will be created in

the photovoltaic sector alone dur-

ing the next decade, with about

20% of these in manufacturing.

IInntteerrnnaattiioonnaall JJoobb GGrroowwtthh ––WWhhaatt ddoo tthhee EExxppeerrttss SSaayy??

The most detailed job study is part

of a 1996 European Green Paper

adopted by the European Par-

liament and subsequently expand-

ed into a White Paper. This paper

cites a study showing that for the

photovoltaic sector alone, well in

excess of 100,000 jobs will be cre-

ated in Europe by 2010, while for

the broader renewable energy sec-

tor, hundreds of thousands of

jobs will be created during the

same time frame. In addition, in

the late 1990’s, the Austrian

Federal Minister for the Envi-

ronment publicly announced the

systems for the purposes of pow-

ering virtually any electrical load. It

covers a broad range of engineer-

ing tasks and disciplines, but it can

be summarised into five main

areas. These are:

� Device and system research

and development;

� Manufacturing, quality control

and reliability;

� PV system design (computer

based), modelling, integration,

analysis, implementation, fault

diagnosis and monitoring;

� Policy, financing, marketing,

management, consulting, train-

ing and education;

� Using the full range of renew-

able energy technologies in-

cluding alternate energy tech-

nologies (such as wind, biomass,

and solar thermal), solar archi-

tecture, energy efficient building

design and sustainable energy.

TThhee BBoooommiinngg PPhhoottoovvoollttaaiicc IInndduussttrryy

The PV industry has been growing

at a rate of 30% per annum, which

is faster than the computer

or telecommunications industries.

Figure K2 shows the explosive

nature of the PV industry growth.

These soaring growth rates are

predicted to continue as the new

market, grid-connected photo-

voltaics on residential houses,

expands. Government initiated

plans throughout the world have

already been formulated for the

implementation of at least three

million additional houses to be

powered by solar cells during the

first decade of the new millenni-

um. One and a half million houses

are targeted for Japan, one million

houses for Europe, and a further

IntroductionIntroductionThe University of New South Wales was awarded a Key Centre

for Teaching and Research in Photovoltaic Engineering which

commenced in January, 1999. This Key Centre has been estab-

lished as part of the Australian Research Council’s Key Centres

Scheme, and was one of only eight such Key Centres awarded

Australia-wide across all disciplines.

FIGURE K1: NEW

DEGREE BROCHURE.

FIGURE K2: MASSIVE GROWTH

IN ANNUAL PHOTOVOLTAIC

PRODUCTION

FIGURE K3: SELLING PRICE FOR

PHOTOVOLTAICS AS A FUNCTION

OF MARKET SIZE.

FIGURE K4: ANTICIPATED JOB

CREATION BY THE YEAR 2004

AS A FUNCTION OF ANNUAL

GROWTH RATE FOR THE

PHOTOVOLTAIC INDUSTRY.

WWhhaatt eedduuccaattiioonn aanndd ttrraaiinniinngg aarree nneeeeddeedd ffoorr tthheessee jjoobbss??

Unfortunately, as identified by many

manufacturers and end users, limit-

ed educational opportunities exist

for engineers to gain the necessary

training and qualifications to suit

the needs of the rapidly expanding

photovoltaics and renewable energy

sectors. For example, Western

Power, who owns all the electricity

grids in Western Australian, has

found it impossible to find appro-

priately trained engineers for its rap-

idly expanding use of renewable

energy technologies such as wind

I N T R O D U C T I O N

K7 �

KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG

� K6

power and photovoltaics. Western

Power has consequently taken the

initiative to fund the establishment

of a new undergraduate engineer-

ing program at Murdoch University

to specifically address this need. In

NSW, photovoltaic manufacturing

is particularly strong with almost all

of Australia’s manufacturing capac-

ity being based in Sydney. A similar

situation exists whereby appropri-

ately trained engineers are unavail-

able. The local photovoltaics indus-

try has been drawing heavily on

graduates from Electrical Engin-

eering at the University of New

South Wales and then subsequently

facilitating additional training for

these graduates to equip them as

photovoltaic engineers. Of the 137

graduates from Electrical Engin-

eering in 1998 at UNSW, 3 of the

students from the top 5 ranking,

entered the local photovoltaics

industry.

PPhhoottoovvoollttaaiicc JJoobbss iinn NNSSWW

A media release in July, 1999

from the Minister for Energy, Mr.

Kim Yeadon, announced that the

growth in the Green Energy

Sector (which includes all aspects

of photovoltaic engineering

including the use of all renewable

energy technologies and energy

efficient building design), is out-

stripping that of the booming

Information Technology industry

in the state of NSW. In addition,

he announced that the expected

job creation in NSW in the

Green Energy Sector for the fol-

lowing 12 month period would

be approximately 1,200 new posi-

tions. Perhaps just as importantly,

the same study revealed that

1,000 new jobs have already been

created in the sector in the previ-

ous 2-3 years.

that 50% of its entire business is

likely to be through renewable

energy technologies by 2050.

Similarly, BP Solar has been

expanding its photovoltaic produc-

tion capacity by a factor of 2 each

year and has announced that it will

grow to a $1 billion per year busi-

ness by 2007.

WWhhiicchh CCoommppaanniieess EEmmppllooyyPPhhoottoovvoollttaaiicc EEnnggiinneeeerrss??

At present, the major companies

employing photovoltaic engineers

include manufacturers, research

organisations, system design and

integration companies, electricity

utilities (such as Pacific Power,

ACT Electricity and Water and

Western Power), and major end

users of products including, for

example, communications compa-

nies such as Telstra. However, the

number of companies employing

photovoltaic engineers is increas-

ing. Many more companies are

recognising the importance of

these energy sources and hence for

appropriately trained engineers.

This demand is being fuelled by

both the environmentally friendly

nature of renewable energy tech-

nologies and also by the technical

advantages inherent in photo-

voltaics. Even major oil companies

are investing heavily in solar tech-

nology, indicating the need for

photovoltaic and renewable energy

engineers. For example, Shell Oil

Company has publicly announced

FIGURE K5: RENEWABLE ENERGY SYSTEMS BASED

ON PHOTOVOLTAICS AND WIND CONVERTERS.

FIGURE K6: SOLAR POWERED

STREET LIGHT.

KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG I N T R O D U C T I O N

K9 �� K8

Key Centre StaffWith the establishment of the Key

Centre, many of the existing staff

from the photovoltaics group at

UNSW took on positions within

the Key Centre. Of particular

importance, Professor Stuart

Wenham became the Director of

the Key Centre, Dr Christiana

Honsberg has been appointed as

Director of Academic Studies,

Mark Silver retains his role as

Business and Technology Manager,

and Rob Largent has been appoint-

ed as Educational Co-ordinator.

The academic staff involved in the

photovoltaics area, formerly part of

the School of Electrical Engin-

eering, have also transferred to the

new budget unit created with the

establishment of the Key Centre.

In the research area, the originally

proposed management structure

has been slightly modified. The

new structure involves appointing

managers for each individual col-

laborative research project with

industry, with each of these man-

agers reporting directly to the Key

Centre Director. This change has

enabled Professor Martin Green to

take on directorship of the new

Special Research Centre which

commenced in the year 2000.

NNeeww AAccaaddeemmiicc SSttaaffff

With the commencement of the

Key Centre, two high profile aca-

demic staff appointments were

made. Dr Armin Aberle, widely

recognized as one of Europe’s

leading photovoltaic researchers

in the crystalline silicon area,

joined UNSW in late 1998 and

the Key Centre in January, 1999.

Dr Aberle was formerly the

Head of the Photovoltaic De-

partment at the Institute for

NNeeww AAddmmiinniissttrraattiivvee OOffffiicceeMMaannaaggeerr

Ms Lisa Cahill joined the Key Centre

as Administrative Office Manager in

June, 1999. Ms Cahill has had many

years of experience working in the

Electrical Engineering School office

including a period as Administration

Officer. Ms Cahill is taking responsi-

bility for the administration and

implementation of the new educa-

tional programs initiated by the Key

Centre with most emphasis to date

being on the development, imple-

mentation and promotion of the

new Bachelor of Engineering in


GoverningCommitteesThe Key Centre has two govern-

ing committees, a Management

Committee that deals with the

day to day running of the

Centre’s activities, and an

Advisory Committee comprising

industry leaders, end-users and

representatives from other insti-

tutions with related interests.

The Advisory Committee pro-

vides advice and direction for the

Management Committee.

AstroPower (Professor Allen Barnett,

Director)

BP Solarex Pty Ltd (David Jordan,

Director, Engineering Best Practice)

Ceramic Fuel Cells Ltd (Dr Bruce

Godfrey, Managing Director)

Pacific Power (Mr Robert Lang,

General Manager/Development)

University Academics

The University of NSW (Professor

Mark Wainwright, Dean,

Engineering)

Australian National University

(Dr Andres Cuevas)

Murdoch University (Professor Phil

Jennings, Dean, Science and

Engineering)

Delaware University (Professor Allen

Barnett)

MMaannaaggeemmeenntt CCoommmmiitttteeee

The management committee meets

fortnightly and comprises the aca-

demic staff members of the Key

Centre, the administrative office

manager, the education officer, the

business manager and the Key

Centre Director. The Dean of

Engineering is also considered to be

a member of the Management

Committee although instead of

attending the fortnightly meetings, he

has regular separate meetings with

the Key Centre Director.

AAddvviissoorryy CCoommmmiitttteeee

The advisory committee meets

annually, although correspondence

with individual members takes

place on a more regular basis. The

emphasis during the last twelve

months has been on the formation

of this committee with the mem-

bership including industry leaders,

manufacturers, academics from

other institutions and representa-

tives of end-users. The member-

ship includes the following:

MMaajjoorr IInndduussttrryyRReepprreesseennttaattiivveess

Pacific Solar Pty Ltd (David Hogg,

Managing Director)

Solar Energy Research (ISFH) in

Germany. In January, 2000, Dr

Aberle was relieved of all teach-

ing responsibilities to the Centre

for Photovoltaic Engineering for

a period of three years to facili-

tate his appointment as Deputy

Director to the new Special

Research Centre.

The other new academic appoint-

ment was Dr Jeff Cotter, previ-

ously awarded a Postdoctoral

Fellowship in Photovoltaics at

UNSW. The quality and interna-

tional competitiveness of Dr

Cotter’s research during his fel-

lowship has been recognised by

his appointment to the academic

staff shortly after the establish-

ment of the Key Centre. Prior to

joining UNSW, Dr Cotter has had

extensive experience in industry

following several years of

employment by AstroPower, one

of the largest photovoltaic manu-

facturers in the USA. In addition

to the industrial experience, Dr

Cotter has a particularly strong

academic record as demonstrated

by his prestigious award for aca-

demic excellence for his perform-

ance in UNSW postgraduate

courses.

DR ARMIN ABERLE

ACADEMIC STAFF

DR JEFF COTTER

ACADEMIC STAFF

MR ROBERT LARGENT

EDUCATION CO-ORDINATOR

DR CHRISTIANA HONSBERG

DIRECTOR OF

ACADEMIC STUDIES

MS LISA CAHILL

ADMINISTRATIVE OFFICE

MANAGER


(Associate Professor Hugh Outhred).

Representatives of the end-users

and other organizations

Solar Energy Industries Association of

Australia (Geoff Stapleton, President

of the NSW Branch)

Sustainable Energy Development

Authority of NSW (Executive

Director)

Australian CRC for Renewable Energy

(Professor Phil Jennings)

Australian CRC for Renewable Energy

(Dr Bruce Godfrey, Chairman of the

Board)

EnergyAustralia (Neil Gordon,

Manager, Sustainable Energy Branch)

Integral Energy (Geoff Stapleton,

Sustainable Energy Branch)

MEMBERS OF THE GROOVE DIFFUSION BAND AFTER PACKING

THE HOUSE AT THE CAT & FIDDLE HOTEL, BALMAIN.

ONLY ENGINEERS WOULD NAME A BAND AFTER THEIR RESEARCH PROCESSES!

1I N T R O D U C T I O N

K11 �


� K10

AutonomousCentreA requirement for the Key

Centre has been its establish-

ment as an autonomous centre

within the University system

with access to the funds it gen-

erates. The University has hon-

oured this commitment, facili-

tating the establishment of a

budget unit independently of

the School of Electrical

Engineering, called the Centre

for Photovoltaic Engineering.

The granting of independence

to the photovoltaic group has

required a lengthy reconciliation

period which was finally con-

cluded during January, 2000.

The new arrangements provide

the Key Centre with access to

all the funds it generates includ-

ing EFTSU’s and research quan-

tum. This arrangement provides

the Key Centre with opportuni-

ty to demonstrate its sustain-

ability as required by the Key

Centre’s Scheme.

1E D U C A T I O N

K13 �

and 12 high school students and capi-

talizing on the involvement with the

World Solar Challenge and also

Sunsprint which involves model solar

car racing for high schools. Other

more conventional forms of promo-

tion have included the production and

distribution of brochures and the pro-

vision of laboratory tours for visiting

high school groups as well as the pub-

lishing of related material at confer-

ences and in journals. A less orthodox

form of promotion has taken place

through the development of the

Virtual World Solar Challenge, an edu-

cational game developed as a teaching

tool for the new degree, which has

been made available on the Centre’s

website for access via the internet. The

Centre has sponsored a corresponding

competition for high school partici-

pants, with more than 7,000 entries

achieved.


� K12

Rapid growth in the renewable

energy sector and in particular

within the photovoltaics industry,

has led to a shortage of appropri-

ately trained engineers. Based on

several international studies, this

shortage is expected to increase

in coming years as the industry

continues to rapidly expand. The

lack of availability of appropri-

ately trained engineers is being

exacerbated by time delays associ-

ated with implementing new edu-

cation and training programs. The

new Bachelor of Engineering is a

four year program which com-

menced in the year 2000. The last

year has been important for

curriculum/course development

in addition to gaining the neces-

sary approvals at school, faculty,

academic board and finally

University Council levels. Formal

approval for the new program has

now been granted. A range of

advanced teaching tools, re-

sources and techniques have been

developed such as the new multi-

media interactive CD-ROM,

developed primarily for the

purposes of two of the new

courses within the new engineer-

ing program.

A key feature of the new program

is the opportunity provided for

each student to choose a second

area of specialization. Ten options

have already been developed

encompassing most engineering

areas although students are given

the opportunity to develop their

own unique strand that encom-

passes their second area of inter-

est. It is anticipated that many of

these alternative areas will be able

to be expanded into a double

degree program through an extra

year of study if desired by the stu-

dent. Throughout the program,

considerable emphasis is placed on

allowing the student to gain hands-

on experience, particularly with

designing and working with photo-

voltaic systems through project

and laboratory work. Major proj-

ects commence in the second year

of the program.

Considerable promotion of the


Photovoltaics and Solar Energy

has taken place during the last year.

This promotion has included the

development of a multimedia CD-

ROM which gives an overview of

the program, related industries, job

opportunities, research activities in

the area, the academic staff devel-

oping and teaching the program,

and so on. Distribution of the CD-

ROM includes all high schools

throughout Australia. Other pro-

motion includes several informa-

tion days at UNSW, demonstra-

tions and tours during the

University open-day, several public

lectures, a symposium for year 11

EducationEducation

SSOOLLAAAA1133664422

PPHHOOTTOOVVOOLLTTAAIICCSS AANNDD SSOOLLAARR EENNEERRGGYY –– FFUULLLL-TTIIMMEE PPRROOGGRRAAMM

BBAACCHHEELLOORR OOFF EENNGGIINNEEEERRIINNGG

BBEE

YYeeaarr 11 HHPPWW HHPPWW

SS11 SS22 UUCC

SOLA1050 Introduction to Solar Energy,

Photovoltaics & Computing 4 3 9

SOLA1060 Chemistry for Semiconductor Devices 0 3 3

ELEC1011 Electrical Engineering 1 6 0 6

ELEC1041 Digital Circuits 0 4 6

*MATH1141 Higher Mathematics 1A 6 0 6

*MATH1241 Higher Mathematics 1B 0 6 6

PHYS1131 Physics 1A 6 0 6

PHYS1231 Physics 1B 0 6 6

Total 22 22 48

*MATH1141 and *MATH1241 may be taken at the ordinary level.


SS11 SS22 UUCC

Selected Strand 5 5 12

SOLA2051 Project in Photovoltaics and Solar Energy 4 3 9

SOLA2020 Photovoltaic Technology and

Manufacturing 4 0 6

ELEC2042 Real Time Instrumentation 0 3 3

MATH2849 Statistics EE 0 3 3

MATH2509 Linear Algebra 0 3 3

SOLA2050 Sustainable Energy 2.5 0 3

SOLA2060 Introduction to Electronic Devices 0 2.5 3

General Education Electives 4 0 6

Total 19.5 19.5 48


SS11 SS22 UUCC

Professional Electives 4 8 18

Selected Strand (continued) 5 0 6

SOLA3055 Renewable Energy Engineering 2.5 0 3

SOLA3540 Applied Photovoltaics 4 0 6

SOLA3507 Solar Cells and Systems 0 4 6

SOLA3054 Renewable Energy Product

Reliability 2.5 0 3

General Education 0 4 6

Total 18 16 48


SS11 SS22 UUCC

Professional Electives 4 4 12

ELEC4010 Introduction to Management for Electrical

Engineers 3 0 3

ELEC4011 Ethics and Electrical Engineering Practice 0 2 3

SOLA4010 Building Integrated Photovoltaics 2.5 0 3

SOLA4012 Grid Connected Photovoltaic Systems 4 0 6

SOLA4013 Current Issues in Photovoltaics 0 2.5 3

SOLA4910 Thesis Part A 5 0 6

SOLA4911 Thesis Part B 0 10 12

Total 18.5 18.5 48

New Bachelor of Engineering inPhotovoltaics and Solar Energy

OOvveerrvviieeww

One of the primary new initiatives of the Key Centre for

Photovoltaic Engineering is the development and establish-

ment of the world’s first new Bachelor of Engineering in


FIGURE K8: NEW CD-ROM ON PHOTOVOLTAICS: DEVICES,

SYSTEMS AND APPLICATIONS: VOLUME 1, DEVELOPED FOR

THE NEW TEACHING PROGRAMS.

FIGURE K9: MULTIMEDIA

CD-ROM DEVELOPED TO PRO-

VIDE INFORMATION ABOUT THE

NEW BE IN PHOTOVOLTAICS

AND SOLAR ENERGY.

FIGURE K10: MODEL SOLAR CARS

LINING UP TO COMPETE IN THE

SUNSPRINT COMPETITION.

FIGURE K11: MODEL SOLAR CAR

DESIGNED FOR THE SUNSPRINT

COMPETITION.

PPrrooggrraamm OOuuttlliinnee

The program approved by the University’s academic board and the University

Council is summarized as follows:

E D U C A T I O N

K15 �

prises 18 Units of Credit (UC)

with the opportunity to subse-

quently select additional Elec-

tives in the corresponding area in

the final two years. The ten

strands available are listed with

the subject(s) comprising the last

6 Units of Credit to be taken in

year 3.


� K14

Years 2 & 3 Strand Options

Students have the opportunity to

select one of eight possible strands

to complement their education in


Engineering, or develop their own

unique strand. Each strand com-

PPrrooffeessssiioonnaall EElleeccttiivveess ffoorr YYeeaarrss 33 && 44

Because of timetable clashes not all combinations of subjects are possible.

HHPPWW HHPPWW

SS11 SS22 UUCC

SOLA5508 High Efficiency Silicon Solar Cells 0 2.5 3

SOLA5011 Solar Cells: Operating Principles and

Technology 0 4 6

SOLA5053 Wind Energy Converters 0 4 6

SOLA5052 Biomass 4 0 6

SOLA5051 Life Cycle Assessment 2 0 3

SOLA5050 Renewable Energy Policy and

International Programs 2 0 3

MECH4720 Solar Energy 0 4 6

MECH4740 Thermal Power Plants 4 0 6

YYeeaarrss 22 && 33 SSttrraanndd OOppttiioonnss

SSttrraanndd 11 CCoommppuuttiinngg aanndd CCoonnttrrooll HHPPWW HHPPWW

SS11 SS22 UUCC

COMP1011 Computing 1A 6 0 6

COMP1021 Computing 1B 0 6 6

COMP2011 Data Organisation 5 0 6

SSttrraanndd 22 EElleeccttrroonniiccss HHPPWW HHPPWW

SS11 SS22 UUCC

ELEC2031 Circuits and Systems 3 3 6

ELEC3006 Electronics A 6 0 6

ELEC3016 Electronics B 0 5 6

or

ELEC3017 Electrical Engineering Design 0 5 6

SSttrraanndd 33 EElleeccttrriicc EEnneerrggyy HHPPWW HHPPWW

SS11 SS22 UUCC

MATH2011 Several Variable Calculus 4 0 6

PHYS2939 Electromagnetism 3 0 3

ELEC2015 Electromagnetic Applications 0 3 3

ELEC3005 Electrical Energy 1 5 0 6

SSttrraanndd 44 CCoommmmuunniiccaattiioonnss HHPPWW HHPPWW

SS11 SS22 UUCC

ELEC2031 Circuits and Systems 3 3 6

MATH2620 Complex Analysis 0 2.5 3

MATH3150 Transform Methods 0 3 3

TELE3013 Telecommunications Systems 1 5 0 6

SSttrraanndd 55 MMaatthheemmaattiiccss HHPPWW HHPPWW

SS11 SS22 UUCC

MATH2011 Several Variable Calculus 4 0 6

MATH2620 Complex Analysis 0 2.5 3

MATH1090 Discrete Mathematics 3 0 3

MATH3141 Mathematical Methods EE 0 4 6

SSttrraanndd 66 MMeecchhaanniiccaall EEnnggiinneeeerriinngg HHPPWW HHPPWW

\\SS11 SS22 UUCC

MECH2601 Fluid Mechanics and Thermodynamics A 4 0 6

MECH2602 Fluid Mechanics and Thermodynamics B 0 4 6

MECH3601 Thermofluid System Design 3 0 3

MECH3602 Advanced Thermodynamics 0 3 3

SSttrraanndd 77 CCiivviill EEnnggiinneeeerriinngg HHPPWW HHPPWW

SS11 SS22 UUCC

CVEN1023 Statics 3 0 4

CVEN1026 Mechanics of Solids 0 3 4

CVEN2023 Engineering Materials 3 0 3

CVEN2322 Introduction to Structure Engineering 1 0 6 6

CVEN3126 Engineering Management 1 0 3 3

SSttrraanndd 88 CChheemmiiccaall EEnnggiinneeeerriinngg HHPPWW HHPPWW

SS11 SS22 UUCC

CEIC0010 Mass Transfer and Material Balance 2 2 4

INDC3010 Thermodynamics 3 0 3

CHEN2030 Heat Transfer 0 3 3

CEIC2040 Applied Electrochemical and Surface

Processes 1.5 0 2

INDC3031 Experimental Design 2 1 3

INDC3041 Corrosion in the Chemical Industry 0 3 3

FIGURE K12: FABRICATION OF

WORLD RECORD SOLAR CELLS IN

THE UNSW LABORATORIES.

VISITS TO THESE LABORATORIES

ARE POPULAR WITH HIGH

SCHOOL STUDENTS.

FIGURE K13: THE HONDA

SOLAR CAR POWERED BY SOLAR

CELLS FABRICATED IN THE

UNSW LABORATORIES. THIS CAR

HOLDS THE RACE RECORD FOR

THE WORLD SOLAR CHALLENGE.

FIGURE K14: STUDENTS LEARN ABOUT GENERATING

ELECTRICITY FROM WIND CONVERTERS.

FIGURE K15: COMMERCIAL SOLAR CELL PRODUCTION LINE.

FIGURE K16: GRID CONNECTED

ROOF TOP PHOTOVOLTAIC

SYSTEM.

1E D U C A T I O N

K17 �

The second year major project will

in general be more structured than

the final year thesis and can involve

group or individual projects. One

exciting aspect is that all students

will submit all of their project

reports as a formatted HTML doc-

ument, which will then be promi-

nently displayed on-line as a part

of the Key Centre's world-wide-

web site. Not all projects will run

each year. Possible projects cur-

rently being planned include:

students and supervisors will live

within the local village to gain an

appreciation of local life style, cus-

toms and culture. Experts will test

the installed systems in conjunc-

tion with the students prior to their

return to Sydney where a report is

to be written to complete the proj-

ect requirements.

Solar Car Project

The solar car project has proved to

be very popular with engineering

students for many years. The overall

aim is to design, develop, build, test

and eventually race such a solar car.

A wide range of individual projects

are available in this area. This project

is perhaps a good example of how

engineers from a broad range of

backgrounds need to work togeth-

er to facilitate the achievement of

overall goals. It also highlights the

importance of photovoltaic engi-

neers gaining a second area of spe-

cialization to bring cross-discipli-

nary expertise to bear on the proj-

ect. During the last year, students

System Training and

Installation in Nepal

Travelling to Nepal or another part

of the developing world to study

and gain hands-on experience in

the use of renewable energy tech-

nologies is an option made avail-

able to students. In particular, stu-

dents will be trained by experts in

the use of photovoltaic systems,

their design, installation and on-

going maintenance requirements.

Students will then proceed to

install their own system on one of

the local dwellings in one of the

villages in Nepal, comprising a

photovoltaic panel, battery backup,

a system controller, appropriate

mounting structures and small

electrical loads such as fluorescent

lights. During their stay in Nepal,


� K16

Electives can also be chosen from

the subjects listed as electives

for Electrical Engineering, Mech-

anical Engineering, Civil Engin-

eering, Environmental Engineering,

Computer Science and Engineering

and Chemical Engineering for

which appropriate pre-requisite

requirements have been satisfied

and which conform to the credit

point requirements.

DDoouubbllee DDeeggrreeeess iinn tthheeSSeeccoonndd AArreeaa ooff SSppeecciiaalliizzaattiioonn

As indicated above, all students

choose a strand in the second year

of the program that gives tuition

and specialization in a second area.

At the completion of the strand,

students will have gained 18 credit

points which in many cases can be

used as a contribution towards

gaining the necessary 60 extra cred-

it points in a second area to gain a

double degree. In general, the

achievement of a double degree in

an approved program will require

an extra fifth year of study.

Ten strand options have already

been developed, although freedom

is given to students to develop

their own strand options through

consultation with staff from the

school responsible for the second

area. These strand options appear

to be quite popular with the new

students who commenced the

program in the year 2000.

EEnnrroollllmmeennttss

The quota for the new program was

set at 30 for the year 2000. High

demand, however, has led to the

enrolment of 41 students for the first

year of the program, with most stu-

dents having University Admission

Index (UAI) scores well above 90

(see Figure K18).

UUnnddeerrggrraadduuaattee PPrroojjeeccttss

Major projects are taken during the

second and fourth years of the

program. The final year thesis can

be taken in virtually any area

encompassed by the Photovoltaics

and Renewable Energy sectors. In

particular, the world class photo-

voltaic laboratories are well suited

to thesis work in the device area,

although many students may prefer

thesis topics encompassing sys-

tem design, applications, device

and system modelling, environ-

mental issues, balance of system

components, control electronics,

policy, reliability issues, manufac-

turing, the range of renewable

energy technologies, life expec-

tancy, and so on.

FIGURE K17: ELECTRICITY

GENERATION FROM PHOTOVOLTAICS

AND WIND GENERATORS CAN WORK

WELL IN MOST COUNTRIES INCLUD-

ING THE DEVELOPING WORLD.

FIGURE K18: HIGH QUALITY STUDENTS ATTTRACTED INTO THE NEW

BE IN PHOTOVOLTAICS AND SOLAR ENERGY WITH MOST STUDENTS

HAVING UAI SCORES ABOVE 90.

FIGURE K19: OLD FASHIONED

WIND GENERATOR.

FIGURE K20: APPLICATIONS SUCH AS SOLAR POWERED VENDING

MACHINES MAKE GOOD STUDENT PROJECTS.

FIGURE K21: STUDENT PROJECTS IN

DEVELOPING COUNTRIES SUCH AS

NEPAL, APPEAR TO BE PARTICULARLY

POPULAR WITH STUDENTS IN THE BE

IN PHOTOVOLTAICS AND SOLAR

ENERGY PROGRAM. PHOTOVOLTAICS

AND RENEWABLE ENERGY SYSTEMS ARE

PARTICULARLY IMPORTANT FOR THE

DEVELOPING WORLD.

1E D U C A T I O N

K19 �

below is an example of this type

of project.

Local Renewable

Energy Systems

Students are able to get involved

with various local renewable

energy systems. One example is

the photovoltaic powered light-

house on Montague Island. This

installation was designed and

installed by engineers from the

Centre for Photovoltaic Engin-

Sustainable Energy Development

Authority (SEDA) in Sydney also

has a range of projects involving

renewable energy technologies,

energy efficiency, sustainable engi-

neering and environmental issues

such as greenhouse gas emission

reduction. SEDA has indicated

their willingness to have students

from the new BE in Photovoltaics

and Solar Energy program

involved in these types of projects.

Solar Cell Production

Line Projects

Possible projects exist in conjunc-

tion with manufacturers who are

licensees of UNSW photovoltaic

technology. These projects could

potentially take a range of forms

depending on the interests of the

student and the needs of the compa-

nies. Licensees of UNSW technolo-

gy exist in many of the major coun-

tries around the world.

eering and provides a good test

bed for on-going system testing,

analysis, modelling and optimiza-

tion. Data loggers are to be

installed to facilitate easy access to

data relating to system perform-

ance. Another example is the wind

generator at Malabar. Negotiations

are presently under way to provide

access for students to the wind

generator at Malabar for the pur-

poses of carrying out a range of

projects with this technology. The


� K18

prepared for, and then raced in, the

World Solar Challenge from

Darwin to Adelaide and then the

Sunrace from Sydney to Mel-

bourne. In the latter of these races,

the students were placed second

until the closing stages of the race

when mechanical failure forced

their withdrawal. In the World

Solar Challenge, the Aurora car

won the race using solar cells fabri-

cated in the laboratories of the


eering at UNSW.

Grid-connected Photovoltaic

Roof-top Systems

Pacific Solar has initiated a program

for installing photovoltaic rooftop

systems throughout Sydney. More

than 3 million photovoltaic powered

houses have already been planned

internationally for implementation

over the next decade. Students

choosing this as their project area will

have the opportunity to study first

hand the design of these systems at

Pacific Solar and then attend and

view the installation of such systems

by experts. Project work will proba-

bly also include testing and monitor-

ing the system performance follow-

ing installation. These systems are all

grid-connected, using the AC mod-

ule concept whereby each individual

photovoltaic module has its own

integral inverter for interfacing to the

electricity grid. Pacific Solar is plan-

ning to install a manufacturing facili-

ty in Sydney capable of producing

more than 130,000 of these modules

each year. The Government has

announced a 50% subsidy for such

systems to ensure rapid market

growth.

Model Solar Car Racing

Sunsprint is a model solar car race

for high school teams. Each school

forms its own team and designs its

own model solar car. Student proj-

ects in this area can include:

involvement with organizing and

running the event; web-based

delivery of results including the

use of movie clips and digital pho-

tographs made available via the

internet; or even co-ordinating the

activities of a given team such as

the high school previously attend-

ed by the particular student.

Development of Multimedia

Presentations

Students interested in carrying out

research in any of the renewable

energy areas are given the opportu-

nity to choose a topic, carry out the

research and then prepare a multi-

media presentation on the topic.

Students will be trained to devel-

op the skills necessary for pro-

ducing multimedia presentations

from their research material,

including web page design,

HTML and DHTML coding,

Macromedia Director anima-

tions, Java and Javascript pro-

gramming, etc. The Virtual

World Solar Challenge described

FIGURE K22: DESIGNING, BUILD-

ING AND RACING SOLAR CARS IS

ANOTHER PARTICULARLY POPU-

LAR PROJECT WITH STUDENTS.

FIGURE K23: THE AURORA

SOLAR CAR WITH SOLAR CELLS

FABRICATED IN THE UNSW

LABORATORIES, WON THE 1999

WORLD SOLAR CHALLENGE.

FIGURE K24: ROOF TOP PHOTOVOLTAIC SYSTEM INSTALLED BY PACIFIC

SOLAR IN SYDNEY. INTERESTED STUDENTS MAY HAVE THE OPPORTUNITY

TO WORK WITH SUCH A SYSTEM.

FIGURE K25: SEVERAL STUDENT PROJECTS RELATE TO THE MODEL

SOLAR CAR RACING ACTIVITIES ASSOCIATED WITH THE SUNSPRINT

COMPETITION FOR HIGH-SCHOOL STUDENTS.

FIGURE K26: IT IS AMAZING WHAT CAN BE USED

TO MAKE A MODEL SOLAR CAR!

FIGURE K27: VARIOUS STUDENT

PROJECTS ARE EXPECTED TO

BE OFFERED IN CONJUNCTION

WITH THE WIND GENERATOR

AT MALABAR.

1E D U C A T I O N

K21 �

New Master of EngineeringScience inPhotovoltaicEngineering

It is currently possible to enroll in

a Master of Engineering Science in

Electrical Engineering which

includes several photovoltaic

device and application based sub-

jects. A new Master of Engi-

neering Science program is cur-

rently being planned and devel-

oped in photovoltaic engineering

which will include a range of new

subjects developed in conjunction

with material and teaching aids

developed for the new Bachelor of

Engineering. The new Master of

Engineering Science program is

expected to be approved by the

Academic Board of UNSW and

University Council over the next

twelve months.

IInntteerraaccttiivvee TTeeaacchhiinnggRReessoouurrcceess

Overview

The increasing prevalence of com-

puters offers many chances to

increase and improve learning

opportunities in the photovoltaic

area though the development of

interactive teaching resources.

ous forms, including "active equa-

tions", interactive graphs or simu-

lations. A teaching grant to devel-

op these concepts based on cog-

nitive load theory was granted

from the CUTSD recently. Based

on this grant, an interactive CD-

ROM, Photovoltaics Devices, Systems

& Applications: Volume I was

developed and published.

An additional important area in the

development of effective teaching

resources is the development of

"simulated laboratories" or "simu-

lated systems" that also invoke

similarities to a "mental game".

Simulated laboratories or systems

have often been cited as a means to

more effectively allow students to

perform simulated experiments.

However, a key limitation in these

approaches has been the absence

of "random" fluctuations that test

students’ understanding and devel-

op their analysis skills. The

"Fantasy World Solar Challenge"

incorporates both elements of a

computer game and random

events into a single, entertaining

teaching package.

IInntteerraaccttiivvee CCDD-RROOMM::

Photovoltaics Devices,Systems & Applications:Volume I

Project Leader:

Dr C. B. Honsberg

The PVCDROM Photovoltaics:

Devices, Systems & Applications:

Volume I is an interactive CD-ROM

that explains the operation, design

and technology of photovoltaic

devices and modules. The CD-

ROM is an ideal introduction to

the solar cell area, with particular

relevance to industry and educa-

tion. It is used in the Applied

Increasing the education opportu-

nities in photovoltaics is particular-

ly important because photovoltaics

is rapidly expanding and it is also

very diverse, both in terms of

where it is geographically sited

(and hence where people wish to

learn about it) and also in the range

of applications.

The development of interactive

teaching resources offers many

benefits to students in photo-

voltaics. For example, interactive,

multimedia animations or simula-

tions improve educational out-

comes by allowing users to visu-

alise important abstract or mathe-

matical concepts. These programs

also take education a step further

by encouraging users to experi-

ment with equations and observe

the relationships between inputs

and outputs. Such an experimental

approach allows the user to devel-

op their own mental model of a

concept, and assists in the stu-

dents’ understanding and ability to

apply these concepts. These inter-

active components may take vari-


� K20

FIGURE K28: MONTAGUE ISLAND.

FIGURE K35: SOLAR LIGHTING AT

UNSW DESIGNED BY

PHOTOVOLTAIC ENGINEERS.

FIGURE K30: VARIOUS PROJECTS

ARE AVAILABLE AT THE UNSW

FACILITIES AT LITTLE BAY WHERE

THE PHOTOVOLTAIC SYSTEMS ARE

GRID CONNECTED VIA INVERTERS.

FIGURE K29: COMPUTER MODEL-

LING OF PHOTOVOLTAIC DEVICES

GREATLY SIMPLIFIES DESIGN AND

ANALYSIS EXERCISES.

FIGURE K33: THE TRACKING

PHOTOVOLTAIC SYSTEM AT

LITTLE BAY.

FIGURE K34: PROCESSING OF

SOLAR CELLS IN A CLEAN ROOM

ENVIRONMENT.

FIGURE K32: BLUESAT IS A

STUDENT PROJECT TO DEVELOP

& LAUNCH A SMALL SATELLITE

USING UNSW SOLAR CELLS FOR

POWERING THE ELECTRONICS.

PPrroojjeeccttss AAvvaaiillaabbllee oonn CCaammppuussA range of other projects areavailable on campus either inthe device area such as throughtesting, characterization andmodelling, or else with applica-tions such as developing orworking with PV poweredwater pumping systems, orworking with the BLUEsat proj-ect. The latter is a student proj-ect involving students frommany disciplines workingtogether to develop and launcha small satellite with photo-voltaic power for all the elec-tronics and testing.

FIGURE K31: COMMERCIAL SOLAR CELL PRODUCTION LINE

MAKES A GOOD ENVIRONMENT FOR STUDENT PROJECTS.

E D U C A T I O N

K23 �

mine the relative importance of

particular inputs. In this CD-

ROM, every major equation is an

active equation. Examples of

active equations are the calcula-

tion of solar cell fill factors as a

function of both series and

shunt resistance and the calcula-

tion of silicon material parame-

ters based on doping.

EducationalCollaborationOverview

A range of collaborations have been

established between the Key Centre

and other educational institutions

and organizations. Some of these

collaborations are taking place

through the range of projects being

established to give students hands-on

experience in the photovoltaic and

renewable energy areas (see last sec-

tion). In general, collaborations with

other institutions such as Murdoch

University and other organizations

such as the Australian CRC for

R e n e w a b l e

ance. Mr Ted Spooner is an active

member of the international IEC

TC82 Photovoltaics Systems

Working Group for development of

standards. He is also a member of

the Australian EL42 and chairman of

the grid connection subcommittee of

EL42. The University of NSW has a

test facility for grid connected PV

inverters at Little Bay in Sydney and

ACRE is in the process of building

an extensive renewable energy sys-

tems test facility in Perth both of

which are managed by Mr Spooner.

MMuurrddoocchh UUnniivveerrssiittyy

Project Leader:


Recently, Murdoch University

expressed an interest in developing

a new Bachelor of Engineering

similar to the program being imple-

mented at UNSW through the Key

Centre. The Director of the Key

Centre, Professor Stuart Wenham,

is co-ordinating the development of

this new "Renewable Energy

Engineering" program at Murdoch

Energy are important for facilitating

the achievement of the Key Centre’s

aim to act as a national focus for

these activities.

AAuussttrraalliiaann CCRRCC ffoorrRReenneewwaabbllee EEnneerrggyy ((AACCRREE))

Project Leader:

Robert Largent (for year 2000)

A new collaboration was established

between the Key Centre and ACRE

in April 2000 with Robert Largent as

Project Leader. Funding will be pro-

vided by ACRE to support educa-

tional activities conducted by the Key

Centre in the areas of internet cours-

es in renewable energy, high school

education and community education

in the renewable energy area. This

collaboration also includes Curtin

University, the Australian National

University and Murdoch University.

ACRE has also expressed an interest

in providing funding for the develop-

ment of specific courses for use

within the new Bachelor of

Engineering in Photovoltaics and

Solar Energy. An example of such is

the development of a "wind" course

for joint use between the Key Centre

at UNSW and Murdoch University

in Perth.

During the last twelve months, fund-

ing for specific projects was provided

by ACRE in the three areas listed

previously and also in the area of

developing new standards. With

regard to the latter, international

standards are under rapid develop-

ment for stand-alone and grid con-

nected renewable energy systems

through IEC TC82 and IEEE com-

mittees. Australian Standards

Committee EL42 has produced a

standard for stand-alone systems

(AS4509). EL42 plans to progres-

sively develop standards for system

components and system perform-


� K22

Photovoltaics Internet-based short

course as well as the new under-

graduate BE in Photovoltaics and

Solar Energy program. Both of

these courses are run by the Centre

for Photovoltaic Engineering at

The University of New South

Wales, Sydney, Australia.

Each page on the PVCDROM

contains a picture or graphic, an

animation, an active equation, an

interactive graph and/or a simu-

lation. Animations are included

to illustrate and assist in the

understanding of particular con-

cepts. For example, a p-n junc-

tion can be more easily under-

stood if the movement of carri-

ers across the junction is animat-

ed. In the animation for p-n

junctions, each carrier moves in a

random direction for a given

period of time. Carriers that

enter the depletion region are

swept to the other side of the

junction, where they eventually

recombine. An excerpt from an

animation is shown below.

Another useful method of allow-

ing students to develop and test

their understanding is to use

interactive graphs or simulation.

Interactive graphs are useful

where there are a limited number

of input parameters, and the out-

put parameter is a commonly

used graph.

Interactive graphs and simula-

tions are quite similar, except that

a simulation typically has a

greater number of describing

equations and input and output

variables. Because of the com-

plexity of the underlying con-

cepts and mathematical equa-

tions, a simulation provides more

outputs or outputs in a different

form than an interactive graph.

An example of a simulation of

the sun’s position is provided.

"Active" equations can be used

that allow a user to enter inputs

and observe the effects. Active

equations are particularly useful

for concepts that have multiple

inputs but only a single output.

They allow users to get a feel for

the correct numbers and deter-

FIGURE K36: EXCERPT FROM AN

ANIMATION OF A P-N JUNCTION.

FIGURE K37: CALCULATION OF SILICON MATERIAL PARAMETERS

USING ACTIVE EQUATIONS.

FIGURE K39: COLLABORATIVE

EDUCATIONAL ACTIVITIES HAVE

BEEN ESTABLISHED WITH THE

AUSTRALIAN CRC FOR

RENEWABLE ENERGY. CURTIN

UNIVERSITY, THE AUSTRALIAN

NATIONAL UNIVERSITY AND

MURDOCH UNIVERSITY ARE ALSO

PART OF THIS COLLABORATION.

FIGURE K40: THE KEY CENTRE

IS COLLABORATING DIRECTLY

WITH MURDOCH UNIVERSITY

TO ASSIST THE LATTER IN THEIR

DEVELOPMENT OF A NEW BE

IN RENEWABLE ENERGY

ENGINEERING.

FIGURE K38: CALCULATION OF THE PATH OF THE SUN AS A FUNCTION

OF LATITUDE, TIME OF DAY AND TIME OF YEAR.

1KKEEYY CCEENNTTRREE FFOORR PPHHOOTTOOVVOOLLTTAAIICC EENNGGIINNEEEERRIINNGG

� K24

University with quite a few sub-

jects to be used from the new



at UNSW. Considerable empha-

sis is being placed on the devel-

opment of material able to be

offered via the internet to satisfy

distance learning requirements

for the students at both institu-

tions. Excellent financial support

is also being provided for this

new Renewable Energy Engin-

eering program at Murdoch, par-

ticularly from Western Power,

the Alternative Energy Devel-

opment Board and the Australian

CRC for Renewable Energy. This

new degree will commence in

2001, one year later than the pro-

gram at UNSW. Overall, the

Murdoch University degree will

have less specialist material in

the photovoltaic area but will

give greater exposure to other

renewable energy technologies

of particular importance in WA

such as biomass and wind gener-

ation. Several subjects developed

for the Murdoch degree will also

be made available to students in

the Photovoltaics and Solar

Energy degree. Professor

Wenham’s co-ordinating role has

been formalized through the

offer of an adjunct appointment

at Murdoch for a 3 year period.

TThhaaiillaanndd UUnniivveerrssiittiieess

Project Leader:

Dr Jeff Cotter

Another activity within the Key


eering is helping overseas universi-

ties who seek collaboration to

enhance undergraduate curriculum

and to improve research expertise

in the renewable energy area. This

activity has immediate benefits to

the foreign institution in addition

to the longer-term benefit of

establishing linkages between these

universities and Australian institu-

tions. Such linkages might lead to

the exchange of undergraduate

students, postgraduate students or

faculty members.

Dr Jeff Cotter recently travelled to

Thailand to visit key personnel at

several universities interested in

photovoltaics: Burapha University

in Bang Saen, Chiang Mai

University in Chiang Mai, and

Ubon Ratchathani University in

Ubon Ratchathani. The main pur-

pose was to discuss issues related

to course curricula, to identify suit-

able teaching resources and to dis-

cuss future research activities in

the renewable energy and photo-

voltaics fields. In addition, Dr

Cotter delivered a one-day work-

shop in Bangkok for a wider audi-

ence that included a brief

overview of renewable energy

resources and technology and

details of recent developments in

photovoltaics technology. In late

March 2000, three Thai faculty

members travelled to Australia

for an 8 week fellowship that

immersed them in both teaching

and research activities at the

Key Centre.

E D U C A T I O N

K25 �

GGeeoorrggiiaa IInnssttiittuuttee ooffTTeecchhnnoollooggyy

Project Leader:


One of the Key Centre academic

staff, Dr Honsberg, traveled to

the Georgia Institute of

Technology for the purpose of

presenting material relating to

the new educational programs,

resources and techniques being

developed at UNSW in the pho-

tovoltaics area. Both institutions

are interested in further discus-

sions relating to possible oppor-

tunities for collaboration and

faculty exchange.

IInntteerrnnaattiioonnaall EEnneerrggyy AAggeennccyy((IIEEAA))

Staff involved:

Dr Muriel Watt

Mr Ted Spooner

(Electrical Engineering)

UNSW is a member of the

Australian Photovoltaic Power

Systems (PVPS) Consortium for

the International Energy Agency

PVPS program, one of the col-

laborative Research and Dev-

elopment agreements established

within the IEA. UNSW responsi-

bilities are shared between

Solarch and the Photovoltaics

Centre.

The overall program is headed

by an Executive Committee com-

posed of one representative

from each participating country,

while the management of indi-

vidual research projects (Tasks)

is the responsibility of operating

agents.

The Australian consortium is

involved with several program

World SolarChallenge EventProject Leader:

Mr Mark Silver (WWW, Logistics)

Project Leader:

Dr Jeff Cotter (Speed of Light II)

Other Staff:


Mr Lawrence Soria

Mr Simon Freedman



This year the Centre continued its

tradition of association with the

World Solar Challenge, the world's

premier solar car event racing over

2000km across Australia from

Darwin to Adelaide. The Centre was

tasks, including Task I - Info-

rmation Dissemination; Task III

– Stand-Alone Power Systems;

Task V – PV Grid Connection;

Task VII – PV in Buildings; and

Task IX – PV in Developing

Countries. The consortium

meets four times a year and a

wide range of topical PV infor-

mation is distributed and dis-

cussed. Photovoltaic Centre staff

have been particularly involved

in the activities of Tasks I, V and

VII, with Muriel Watt preparing

the Australian contribution to

the International PV Survey

Report and Ted Spooner

involved with the development

of international grid connection

guidelines.

FIGURE K42: WIND GENERATOR

AT MURDOCH UNIVERSITY

TO BE USED FOR EDUCATIONAL

PURPOSES.

FIGURE K43: LINKAGES HAVE

BEEN ESTABLISHED BETWEEN

THE KEY CENTRE AND

THAILAND UNIVERSITIES.

FIGURE K41: REMOTE AREA

POWER SUPPLY AT MURDOCH

UNIVERSITY.

FIGURE K44: WEB-BASED DISSEMINATION OF INFORMATION

ELATING TO THE 1999 WORLD SOLAR CHALLENGE EVENT.

E D U C A T I O N

K27 �

about the new Bachelor of En-

gineering in Photovoltaics and

Engineering.

TThhee AAuussttrraalliiaa PPrriizzeeSSyymmppoossiiuumm

Project Leaders:

Mr Mark Silver


During last year, the Key Centre

held a symposium for years 11

and 12 high school students.

Featured at the symposium were

Professors Green and Wenham,

the 1999 recipients of the

Australia Prize for Energy

Science and Technology. Other

presentations at the symposium

included: an introduction and

SSuunnsspprriinntt-MMooddeell SSoollaarr CCaarrRRaacciinngg ffoorr HHiigghh SScchhoooollSSttuuddeennttss

Project Leader:

Mr Robert Largent

The Key Centre has taken over

responsibility for organizing the

statewide Sunsprint competition.

Sunsprint is a model solar car rac-

ing competition held annually for

teams of high school students who

design, build and ultimately race

their model cars against other high

school teams. In the most recent

event, 42 entries were received

statewide, involving approximately

300 students. These projects pro-

vide excellent educational oppor-

tunities for the students involved

as they learn more about photo-

voltaics, project design and team-

work. The Key Centre and the

Faculty of Engineering at UNSW

recognize the importance of this

event, not only for its direct educa-

tional benefits, but also as a means

of giving students insight into

engineering in general and specifi-

cally photovoltaic engineering and

solar energy. The winning high

school was Dubbo Christian

School, with the top four placed

cars being sponsored to participate

in the National Titles held in

overview of the new Bachelor

of Engineering in Photovoltaics

and Solar Energy by Dr

Christiana Honsberg; a presen-

tation and demonstration by the

solar car team; and various edu-

cational demonstrations de-

signed to teach students about

engineering, electricity, photo-

voltaics and their potential for

the future. Despite cancellations

due to the teachers’ strike, 180

students from 19 high schools

attended the symposium to

learn more about photovoltaic

devices and applications and

their future potential.


� K26

proud to have been selected by the

race organisers to once again write

the official race report Speed of Light

II: World Solar Challenge and to pro-

vide Internet support by way of a

graphical display of race progress

linked from the race organiser's

home page.

Our special WWW site was designed

by undergraduate thesis student

Simon Freedman and brought on

line to provide global race enthusiasts

and the general public with "on the

fly" consolidated race progress and

information. The site also promoted

the World's First Undergraduate

Degree Program in Photovoltaics

and Solar Energy at UNSW.

Official race data was displayed on an

interactive map of Australia along

with ticker tape headlines, daily race

reports, photo images, videos and

links to the home pages of the official

race organisers and race teams. The

bulk of information for the web site

was provided by Dr Jeff Cotter's in

field "Speed of Light II" team which

took over 2,000 images en route.

At its peak during the World Solar

Challenge, our special race server

downloaded over 210,000 pages in

one day and generated interest in

the Centre ‘s web site which

increased five fold to almost 11,000

requests a day. After the race the site

lives on as a valuable record of race

details and images which will be fur-

ther bolstered by the release of the

book/report Speed of Light II: World

Solar Challenge.

Promotion ofEducationalPrograms

BBrroocchhuurreess

Project Leader:

Ms Lisa Cahill

A range of brochures have been pro-

duced and printed for distribution.

These have been sent to all high

schools in Australia as well as being

used extensively wherever possible to

publicise the educational programs.

Brochures include information

PPHHAASSEE CCDD-RROOMM

Project Leader:

Mr Robert Largent

Educational Officer, Robert Largent,

has co-ordinated and managed a

team of people in the development

of a multimedia CD-ROM for the

primary purpose of promoting the


Photovoltaics and Solar Energy. This

CD-ROM gives an overview of pho-

tovoltaics and the range of renew-

able energy technologies. It also pro-

vides background material on the

growth in the related industries and

the corresponding job creation that

has necessitated the establishment of

this program. A detailed outline of

the course has been provided as well

as descriptions of the individual sub-

jects and their content. An introduc-

tion to the staff of the Key Centre

and their background areas of

expertise are provided. There is also

an overview of the achievements of

the Photovoltaic Centre during the

last 15 years of world leadership in

device research and technology

development. Approximately 12,000

FIGURE K46: CD-ROMS DEVELOPED TO PROMOTE THE NEW

DEGREE IN PHOTOVOLTAICS AND SOLAR ENERGY.

FIGURE K47: ELECTRICITY DEMON-

STRATION FOR STUDENTS.

FIGURE K49: THE SUNSPRINT

STATE-WIDE COMPETITION FOR

MODEL SOLAR CAR RACING IS

HELD AT UNSW.

FIGURE K48: EACH MODEL

SOLAR CAR IS DESIGNED AND

DEVELOPED BY A TEAM OF HIGH

SCHOOL STUDENTS.

FIGURE K50: SOLAR CAR DESIGNED, DEVELOPED,

BUILT AND RACED BY UNSW STUDENTS.

FIGURE K45: SOLAR CARS

COMPETING IN THE

WORLD SOLAR CHALLENGE.

sheets on a range of topics, leaflets to

advertise particular Centre activities

and brochures aimed specifically to

disseminate information about the

new degree program.

copies of the CD-ROM have been

produced and made available free of

charge to careers’ advisors in all high

schools throughout Australia and to

anyone else interested in learning

1E D U C A T I O N

K29 �

The VWSC has been developed

under the leadership of Dr Jeff

Cotter as an educational tool with-

in the new degree program and

also for promotional purposes.

Solar-powered racing cars are par-

ticularly suited for educating peo-

ple of all levels about the engineer-

ing of photovoltaic systems. They

have broad appeal because they are

quite fascinating and dynamic, and

since there are always winners and

losers, there is an element of

drama, strategy and tactics that is

not found in most PV systems.

Solar-powered racing cars also rep-

resent a truly multi-disciplinary

engineering problem, which makes

them an ideal learning opportunity

for university and high-school stu-

dents. In fact, more than three-

quarters of the entrants in the lat-

est World Solar Challenge race from

Darwin to Adelaide were either a

university or a high-school team.

Solar racing cars bring together the

principles of several engineering

fields like no other project: automo-

tive engineering (suspension and

siderable simplification of the techni-

cal issues of racing car design, which

was accomplished with a "Design

Workshop", where players select

from a list of options for the body of

the car, the solar array, the battery and

other car features. Integral to the

workshop is a set of tutorial pages

that provide a brief overview on each

of the main technical issues of racing

cars. Each entrant must then design

their own car within the overall budg-

etary constraints imposed.

Once the design phase is complete

(it usually takes five to ten minutes

to complete), the player races in the

"Virtual World Solar Challenge", a

simulated race from Darwin to

Adelaide. The racing console pro-

vides important telemetry, weather

and strategy information in a graph-

ical format. The main display indi-

cates the present speed, battery-

state-of-charge, solar intensity,

motor power and weather forecast,

all displayed on a virtual car dash-

board, along with a front screen

view out of the car. Three small

graphs on the main console display

the battery-state-of-charge, speed

and solar intensity for the last 9 hours

of racing. The complete telemetry

history is available on a separate page.

To give the game the flavour of a

race, several computer-generated

players compete in each race, and

steering), aerospace engineering

(aerodynamics), chemistry (batter-

ies), mechanical engineering (chas-

sis design), photovoltaics (solar cells

and arrays), and electrical engineer-

ing (telemetry, electronics, motors

and communication). These cars

are also one of the most highly

optimised PV systems, and there-

fore there is significant depth in

addition to breadth in these engi-

neering problems.

Furthermore, solar racing cars have

several interesting design constraints

and conditions that are not usually

associated with PV systems. For

example, array area and battery

capacity are restricted by race regula-

tions, and system cost is not always

an important factor. Also, the weath-

er conditions and forecast, including

cloud cover, wind and temperature,

take on a whole different meaning

for racing cars.

During the last year, the Key Centre

set out to capture the essence of

designing and racing a solar car in a

fast, visually pleasing, browser-based

game at a level suitable for secondary

school children. This requires con-


� K28

Adelaide in conjunction with the

World Solar Challenge.

The two major sponsors of the

Sunsprint competition were the


Engineering and the Faculty of

Engineering at UNSW. Generous

sponsorship was also provided

by the Australian CRC for

Renewable Energy, BP Solarex,

Farnow Pty Ltd, and General

Technology Pty Ltd.

This year, the Key Centre

intends to make even greater use

of this event as a means for edu-

cating high school students

about photovoltaics, renewable

energy technologies and the new



In conjunction with this, greater

emphasis will be placed on using

web-based dissemination of

information, both prior to and

during the Sunsprint competition

to provide high schools around

the State and country with race

information and educational

material.

SSppoonnssoorrsshhiipp ooff SSoollaarr CCaarr PPrroojjeecctt

Project Leaders:

Dr Jeff Cotter

Associate Professor Paul Basore

The Centre has provided signifi-

cant levels of sponsorship for the

UNSW solar car, for two purposes.

The first purpose is to create addi-

tional opportunities for students

from the Centre to engage in solar

energy related projects. Dr Jeff

Cotter is actively involved in this

area in terms of team management

and technology development. The

second purpose is to promote the



program. Racing team members

fulfill their sponsorship obligations

by distributing brochures and CD-

ROMs on behalf of the Key

Centre at Solar Car Races and

other activities. Team members

also provide demonstrations and

presentations at Key Centre pro-

motional activities such as the

Australia Prize Symposium. In addi-

tion, they have participated and

assisted in the production of a pro-

motional video for the new BE in


VViirrttuuaall WWoorrlldd SSoollaarrCChhaalllleennggee ((VVWWSSCC))

Project Leader:

Dr Jeff Cotter

Other Staff:

Mr Mark Silver

Mr Simon Freedman

FIGURE K51: CONSOLE

FOR THE VIRTUAL WORLD

SOLAR CHALLENGE. THIS CAN

BE FOUND ON THE CENTRE FOR

PHOTOVOLTAIC ENGINEERING

WEBSITE.

FIGURE K52: BATTERIES ARE

IMPORTANT FOR SOLAR CARS.

FIGURE K53: SOLAR CAR

PRODUCED BY LAKE

TUGGERANONG HIGH SCHOOL

FROM WHERE SEVERAL NEW

STUDENTS HAVE ENTERED THE

NEW UNSW DEGREE.

FIGURE K54: MANY PARTS

GO TOGETHER TO MAKE UP

A SOLAR CAR.

FIGURE K55: DESIGNING CARS

FOR THE VWSC.

FIGURE K56: EDDIE FU, WINNER OF THE MOST RECENT VWSC NATIONAL

COMPETITION FOR HIGH SCHOOL STUDENTS RECEIVES HIS CASH PRIZE

AND PLAQUE FROM PROFESSOR WENHAM. KINGSGROVE HIGH SCHOOL

PRINCIPAL, MR BOB IRELAND, RECEIVES THE CORRESPONDING PLAQUE

ON BEHALF OF HIS SCHOOL.

FIGURE K57: DR JEFF COTTER

GIVING DEMONSTRATIONS

TO STUDENTS INVOLVING

ELECTRICITY.

E D U C A T I O N

K31 �

mation kits, brochures and CD-

ROMs were also made available at

this location. Thirdly, the

Sunsprint model solar car racing

took place in the Quadrangle,

under the leadership of Robert

Largent. Based on the numbers of

on-lookers, this appeared to be

the most well attended activity on

campus. Large numbers of stu-

dents from high schools through-

out Sydney and NSW attended

throughout the day as their

respective teams competed in the

Sunsprint competition. Centre

staff, where possible, mixed with

the students providing informa-

tion and advice about the new

degree in Photovoltaics and Solar

Energy. Fourthly, short lectures

were provided by Professor

Wenham in the Matthews

Theatre, specifically for the pur-

pose of providing information

and advice relating to the new

engineering degree. These lec-

tures were particularly well

attended thanks to advertising

that took place at the other three

venues listed above.

SSttuuddeenntt VViissiittss

Project Leader: Mr Robert Largent

Various student visits have taken

place as groups from specific schools

have toured the photovoltaic labora-

tories. Similarly, Centre staff have

made themselves available at various

times throughout the year to give pre-

sentations at specific schools and

high-profile events such as Sci Fest.

At Sci Fest the Centre for

Photovoltaic Engineering in conjunc-

tion with the UNSW Outreach

Centre for Sciences entertained and

educated over 3,500 students in the

fields of energy, high-voltage electric-

ity and magnetism.

PPrroommoottiioonnaall VViiddeeoo

Project Leaders:

Mr Robert Largent


The Key Centre has jointly

funded, with the Faculty of

Engineering, a promotional

video based on solar car racing

activities. The original scope of

the video has been broadened to


� K30

the current standings are dis-

played on a small leader board.

Of course, as in just about any

computer-based game, there is a

"World Records" screen contain-

ing the all-time top 1,000 entries.

A high school competition is

conducted anually with a cash

prize and plaque for the most

recent winner, Eddie Fu from

Kingsgrove High School. Since

the game went on-line, it’s been

played over 7000 times by people

from all over the world.

The game can presently be found

on the World Wide Web at

www.pv.unsw.edu.au. It is open

to players of any age or affilia-

tion and can be played as many

times as desired.

IInnffoorrmmaattiioonn DDaayyss

Project Leader:

Ms Lisa Cahill

Several information days have been

held during the last year. The faculty

of Engineering has widely advertised

these events to high school students.

The events have varied in nature, but

in general include activities such as

short lectures, attendance at informa-

tion desks, tours of the photovoltaic

laboratories, various demonstrations

involving photovoltaic technology

and systems, exposure to the VWSC

and the provision of information kits

for all enquirers. These information

days have, in general, involved Key

Centre staff and have also benefited

greatly through contributions from

various PhD students.

UUnniivveerrssiittyy OOppeenn DDaayy

Project Leaders:

Mr Mark Silver (Demonstrations

& Tours)

Mr Robert Largent (Sunsprint Competition)

Ms Lisa Cahill (Information Desks)

Professor Stuart Wenham (Public Lectures)

The University Open Day was a

major event for the Centre for

Photovoltaic Engineering staff

and postgraduate students. Pro-

motional activities took place at

four different locations through-

out the day. Firstly, two staff

members attended information

desks in the Roundhouse to pro-

vide advice, information, and

information kits to all enquirers

about the new BE in Photo-

voltaics and Solar Energy.

Secondly, outside the Science

Theatre, a couple of demonstra-

tions were displayed and operated

throughout the day, including

the solar car and solar powered

orange juicing machines. Infor-

FIGURE K58: PV DISPLAYS AT

UNIVERSITY OPEN DAY.

FIGURE K59: PROFESSOR

WENHAM DISCUSSES THE NEW

BE IN PHOTOVOLTAICS AND

SOLAR ENERGY WITH STUDENTS

FROM KINGSGROVE HIGH

SCHOOL.

FIGURE K60: TWO STUDENTS LEARNING ABOUT ELECTRICITY.

FIGURE K61: THE 1999 AUSTRALIA PRIZE SYMPOSIUM TOOK PLACE

TO RAISE HIGH SCHOOL AWARENESS OF PHOTOVOLTAICS AND

THE NEW DEGREE IN PHOTOVOLTAICS AND SOLAR ENERGY.

include the use of all UNSW

technologies used in the solar

car racing events, particularly the

solar cell technologies that have

been preferred by the leading

cars in most races over the last

decade. The video will also

include material specifically

relating to the new degree in


and will even include interviews

with students enrolling in the

new program.

PPuubblliisshheedd MMaatteerriiaall

Various opportunities have existed

for publishing educational material

about the new undergraduate engi-

neering program. Papers have been

either published at or accepted for

publication at the 11th International

Photovoltaic Science and Engi-

neering Conference (Japan), ANZS-

ES Conference (New Zealand),

the 16th European Photovoltaic

Solar Energy Conference (Scotland),

and the ISREE 2000 Seventh Inter-

national Symposium on Renewable

Energy Education (Norway).

In addition, a paper specifically

focusing on the innovative

aspects of the new program has

been accepted for publication in

a special issue of Solar Energy

Materials and Solar Cells while a

manuscript detailing the new

degree program was published

in the special educational issue

of the ISES trade journal, Solar

Progress. Other publications

include many published articles

in the printed media as well as

interviews for radio and televi-

sion. The latter articles and

interviews have been conducted

for their newsworthy value and

hence have not incurred costs

for the Key Centre.

1

Industry Funded Collaborative ResearchIndustry Funded Collaborative Research


� K32

The Key Centre has successfully

achieved its aim of establishing

collaborative research programs

with all Australian manufacturers

of photovoltaic devices. The

final program to be established

was a collaboration with Solarex

to develop a new technology to

satisfy the requirements of their

multi-crystalline silicon sub-

strates All the collaborative

research projects conducted

under the umbrella of the Key

Centre are self funding with no

ARC Key Centre funds being

used to support the work. This is

consistent with the guarantee

provided by the applicants in the

original Key Centre proposal

stating that all industry collabo-

rative research projects would be

conducted on a "full incremental

cost recovery basis". Due to the

importance and success of some

of these collaborative research

projects, academics from the Key

ect to have been established under

the joint collaborative research agree-

ment between Europe and Australia.

Despite this however, no funding has

yet been forthcoming from the

Australian Government to support

the project. In comparison, signifi-

cant levels of funding (well in excess

of $100,000 per year) is being con-

tributed through the European

Commission JOULE III Program

(contract JOR3-CT98-0294) to sup-

port our European partners from

England and Spain. To allow addi-

tional areas of academic interest to

be explored in this work, funding has

also been contributed from the ARC

Special Investigator’s Award, in the

name of Professor Wenham.

Virtually all commercially pro-

duced silicon solar cells suffer

from high rear surface recombina-

tion velocities. This does not in

general seriously degrade device

performance, as in general the sub-

strate thicknesses are greater than

the minority carrier diffusion

lengths. Future generations of

commercial technology, however,

need to be able to utilise substan-

tially thinner substrates to improve

the economics and also potentially

give performance enhancement.

At present, the use of thinner sub-

strates with existing commercial

cell technology will simply lead to

performance degradation.

This collaborative research pro-

gram has been established with

BP Solar to develop a rear contact-

ing scheme that simultaneously

achieves a much lower rear surface

recombination velocity. Direct

comparison between devices fabri-

cated using these new designs and

devices using more conventional

contacting schemes typical of

those used commercially, has led to

the demonstration of approxi-

Centre have been able to success-

fully apply for other funding to

support the work such as through

the SPIRT Grant Scheme and the

European Commission JOULE

program.

Project with BP Solar (now BP Solarex)

Project Leader:


Other Staff:

Dr Tim Bruton (BP Solar)

Mr Nigel Mason (BP Solar)

PhD Students:

Ms Linda Koschier

Mr Stephen Pritchard

This project has been initiated by

BP Solar, who is directly funding

the corresponding work at UNSW.

It appears that this is the only proj-

I N D U S T R Y C O L L A B O R A T I O N

K33 �

mately 40mV improvement in

open circuit voltage and a corre-

sponding performance enhance-

ment of 5-10%. Importantly, this

performance enhancement will

increase significantly as thinner

substrates are used.

The work in this project at

UNSW should come to comple-

tion during the next year with the

expected performance gains hav-

ing been achieved. The next

stages of this work will involve

transferring these developments

to BP Solar and eventually to

large scale production. As a pre-

liminary step towards these latter

goals, a PhD student, Linda

Koschier, working on this project,

traveled to BP (UK) for approxi-

mately one month to investigate

the feasibility of fabricating similar

devices using the BP Solar facili-

ties. This trip was also fully funded

by BP Solar.

Project withEurosolare

Project Leader:


Other Staff:

Dr Jeff Cotter

Dr Francesca Ferrazza

(EuroSolare, Italy)

PhD Student:

Mr Bryce Richards

This project is being funded directly

by Eurosolare from Italy who

requested this collaborative project

following their licensing of the

buried contact technology. Addi-

tional funding was successfully

gained through the ARC SPIRT

the successful completion of the

technology optimisation program.

The first stage of the correspon-

ding technology transfer took

place recently in the laboratories at

UNSW during which Eurosolare

technicians, researchers and pro-

duction staff were trained in the

new technology.

Project with PacificSolar Pty Ltd

Project Leaders:



Other Staff:

Mr Robert Bardos

Dr Tom Puzzer

Non-UNSW Staff:

Dr Z. Shi (Pacific Solar, Sydney)

Dr A. B. Sproul (Pacific Solar, Sydney)

PhD Students:

Mr Oliver Nast

Mr Nick Shaw

Pacific Solar Pty Ltd was estab-

lished as a joint venture between

Pacific Power and UNSW for the

purpose of commercializing the

new generation of thin film tech-

nology developed at UNSW. Due

grant scheme in the name of Dr.

Honsberg. This additional funding

has facilitated a broadening of the

scope of the project to include

work not considered to be of

immediate commercial application

but nevertheless closely related to

the basic concepts. No Key Centre

funding has been used to support

this project.

Despite the commercial success of

the buried contact solar cell, a sig-

nificant deterrent to the technolo-

gy’s uptake has been the necessity

for industry to invest in entirely

different infrastructure and equip-

ment for it’s manufacture, com-

pared to existing screen printed

cell technology. The aim of this

collaborative research program

with Eurosolare is to adapt the

buried contact solar cell for fabri-

cation using existing screen print-

ing equipment and infrastructure.

TTeecchhnnoollooggyy TTrraannssffeerr

A highlight of this collaboration

and an indication of its success has

been Eurosolare's decision to

license the UNSW technology.

This decision has been made prior

to the completion of the project,

indicating the confidence held for

Introduction

The Key Centre’s research involvement is very much

motivated by its importance to the educational programs. It

therefore focuses on industry collaborative research involv-

ing technologies of commercial and educational importance.

FIGURE K62: THE KEY CENTRE HAS A COLLABORATIVE RESEARCH

PROJECT WITH BP SOLAR, THE WORLD’S LARGEST PHOTOVOLTAIC

MANUFACTURER AND LICENSEE OF UNSW TECHNOLOGY.

FIGURE K63: EUROSOLARE KEY PERSONNEL IN ATTENDANCE AT

UNSW DURING TECHNOLOGY TRANSFER AND MEETINGS IN

RELATION TO THE COLLABORATIVE RESEARCH.

I N D U S T R Y C O L L A B O R A T I O N

K35 �

excessive degradation in minori-

ty carrier lifetimes. This con-

straint in general makes it diffi-

cult to produce heavily diffused

regions beneath metal contacts.

In this new collaborative

research program negotiated

with Solarex, new approaches

for selective diffusion are being

developed and used to provide

heavily doped regions at the

semiconductor surface where

the metal contacts are to be

located. Self-alignment for the

metallization is a further aim, to

be achieved by ensuring that the

integrity of an overlying dielec-

tric layer is destroyed during or

prior to the selective doping as

is the case with the convention-

al buried contact solar cell.

Producing the metal contact in

this way may alleviate the need

for high temperature exposure

of the multi-crystalline sub-

strates. Nevertheless, the new

technology appears capable of

still achieving very fine line

widths and hence many of the

corresponding high perform-

ance attributes normally associ-

ated with the buried contact

solar cell. Furthermore, the

heavy doping beneath the metal

provides excellent ohmic con-

tact as well as minimising the

contribution to the dark satura-

tion current from the metal/sili-

con interface.

Funding for this work, will be

provided by Solarex, with addi-

tional funding being sought

through alternative schemes,

such as the SPIRT Grant

Scheme. As is consistent with

the Key Centre policy, no ARC

Key Centre funding will be used

to support this project. Work is

expected to commence during

the next twelve months but may

be delayed due to the merger

between the major oil compa-

nies BP and Amoco.

Inverter Design

Project Leaders:


Dr Sean Edmiston (Pacific Solar,

Sydney)

Other Staff:


Mr Ted Spooner (Electrical

Engineering)

Mr David Roche

PhD Student:

Mr Bradley O’Mara

The new Pacific Solar product is

expected to be a photovoltaic

module with integral inverter

for grid connection. A major

research program has been

established by Pacific Solar to

develop appropriate low-cost,

high-efficiency, high-reliability

inverters. The collaborative pro-

gram was established with

UNSW well before commence-

ment of the Key Centre,

with the aim being to make

available the vast experience,

facilities and equipment of

UNSW and its researchers to

assist with the development

of this new inverter. As work on

this project nears completion,

the collaboration has taken on

more the form of a consultancy

with work only taking place

when requested by Pacific Solar

who funds the work.


� K34

to commercial sensitivities, the

commercial implementation of

the technology takes place

exclusively at the premises of

Pacific Solar, with no involve-

ment from UNSW. However,

this collaborative research pro-

gram has been established,

whereby the expertise and facili-

ties of UNSW are able to be

used to assist in characterizing

and analyzing materials and

device structures to comple-

ment the commercialization

program at Pacific Solar. The

success of this collaborative

project is partly attested to by a

recent press release from Pacific

Solar announcing the successful

implementation of pilot pro-

duction of the new technology

six months ahead of schedule.

Pilot production modules are

approximately 30cm x 40cm as

shown in Figure K65. The com-

pany anticipates scaling up

the technology to full-

scale production in

the near future.

Substantial lev-

els of fund-

ing have

been provid-

ed by Pacific

Solar to support

this collaborative

project. Additional

funding has been suc-

cessfully sought through

the ARC SPIRT Scheme

in the names of Wenham,

Sproul and Shi. To allow further

broadening of the scope of this

work to include the study of

metal induced crystallization for

forming continuous polycrys-

talline silicon layers of high

quality directly onto glass, fund-

ing has also been made available

from the ARC Special

Investigator’s Award in the

name of Professor Wenham. No

Key Centre funding has been

used to support this work.

Project withSolarex (now BP Solarex)

Project Leader:


Other Staff:


Dr Jeff Cotter

Multicrystalline silicon substrates

in general cannot withstand the

same high temperature exposure

as single crystal silicon substrates.

Prolonged high

t e m p e r a t u r e

e x p o s u r e

c a u s e s

FIGURE

K65:

THIN FILM

PHOTOVOLTAIC

MODULE FABRICATED

ON THE PACIFIC SOLAR

PILOT PRODUCTION LINE

USING UNSW DEVELOPED

TECHNOLOGY.

FIGURE K64: DR SHI IN THE LABORATORIES AT PACIFIC SOLAR,

WHERE COLLABORATIVE RESEARCH WORK IS CONDUCTED BETWEEN

UNSW AND PACIFIC SOLAR.


K37 �

Nast, O., Brehme, S., Neuhaus, D.-H. and

Wenham, S.R., Polycrystalline Silicon Thin

Films on Glass by Aluminium-Induced

Crystallisation, IEEE Trans. on Electron

Devices, Vol. 46, p. 2062, 1999.

Nast, O., Brehme, S., Pritchard, S., Aberle,

A. G., and Wenham, S. R., Aluminium-

Induced Crystallisation of Silicon on Glass for

Thin-Film Solar Cells, Solar Energy Materials

and Solar Cells.

Patents and Patent

ApplicationsGreen, M. A., Wenham, S. R., Ji, J. J.,

Basore, P. A., Shi, Z., Thin Films With Light

Trapping, International Patent No.

PCT/AU99/00979, 1999.

Wenham, S. R., Green, M. A., Honsberg, C.

B. Metallisation for Buried Contact Solar Cells,

Australian Patent, April 1999.

Research Reports and

Non-Refereed PublicationsA. B. Sproul, T. Puzzer and R. Bardos, TDG

Device Characterisation Progress Report, Pacific

Solar Final Reports, Volume 5, February,

1999, pp41-43.

Aberle, A. G. and Wenham, S. R., Overview

on the high-efficiency solar cell research activities at

the University of New South Wales, Symposium

Proceedings, Research Collaboration Sym-

posium, 1st Australian Technology Week in

Taiwan, Taipei, Taiwan, April 1999.

Bardos, R., TDG Device Characterisation

Progress Report, Pacific Solar Final Reports,

Volume 5, May, 1999, pp199-202.



Volume 5, June, 1999, pp219-220.



Volume 5, September, 1999, pp349.



Volume 5, November, 1999, pp439-440.

Bruton, T. M., Mason, N. B., Ruiz, J. M. and

Wenham, S. R., Next Generation 20% efficient sil-

icon solar cells – NEXTGEN First Periodic

Report (1/7/98 to 31/12/98), The European

Commission JOULE III, Contract JOR3-

CT98-0294, March, 1999, 9 pages.

Bruton, T. M., Mason, N. B., Ruiz, J. M. and

Wenham, S. R., Next Generation 20% efficient

silicon solar cells – NextGen Second Periodic

Sproul, A. B., TDG Device Characterisation


Volume 5, June, 1999, pp217-218.



Volume 5, July, 1999, pp259-262.



Volume 5, August, 1999, pp301-304.



Volume 5, September, 1999, pp343-348.



Volume 5, November, 1999, pp433-438.



Volume 5, December, 1999, pp471-476.

Wenham, S. R., Eurosolare Technology Transfer

Report, April 1999, 114 pages.

Wenham, S. R., Technical Progress Report –

NEXTGEN, presented to BP Solarex, 23rd

March, 1999, 16 pages.

Wenham, S. R., Koschier, L. M. and Green,

M. A., NEXTGEN Annual Report, submitted

to BP Solarex, 12th August, 1999, 4 pages.

Wenham, S. R., Technical Progress Report –

NEXTGEN, presented to BP Solarex, 10th

February, 1999, 2 pages.

Report (1/1/99 to 30/6/99), The European

Commission JOULE III, Contract JOR3-

CT98-0294, September, 1999, 18 pages.

Cotter, J., Honsberg, C., Wenham, S. R. and

Leo, T., Proposed Collaborative Agreement

between UNSW and Solarex, February, 1999,

10 pages.

Green, M. A. and Wenham, S. R., Technical

Progress Report – NEXTGEN, presented to

BP Solarex, 10th June, 1999, 12 pages.

Honsberg, C., Cotter, J., Silver, M. and

Wenham, S., Technical Report on Progress:

UNSW/Eurosolare collaboration, August

1999, 5 pages.

Koschier, L. M., Progress Report on

NEXTGEN Activity, BP Solarex, Sunbury,

December, 1999.

Puzzer, T. and Bardos, R., TDG Device

Characterisation Progress Report, Pacific Solar

Final Reports, Volume 5, December, 1999,

pp477-478.

Puzzer, T., TDG Device Characterisation


Volume 5, April, 1999, pp151-162.

Puzzer, T., TDG Device Characterisation


Volume 5, May, 1999, pp209-210.

R. Bardos, TDG Device Characterisation


Volume 5, April, 1999, pp149-150.

Richards, B., Proposed work for

UNSW/Eurosolare collaboration, Presented to

Eurosolare, March 1999, 11 pages.

Sinton R., and Sproul, A. B., Material

Characterisation Progress Report, Pacific Solar

Final Reports, Volume 5, January, 1999,

pp15-20.

Sproul, A. B., STDG Device Characterisation


Volume 5, April, 1999, pp145-148.



Volume 5, March, 1999, pp97-100.

Sproul, A. B., Puzzer, T. and Bardos, R.,

TDG Device Characterisation Progress Report,

Pacific Solar Final Reports, Volume 5,

October, 1999, pp395-400.



Volume 5, May, 1999, pp203-208.


� K36

EducationBooks and CD-ROMsAberle, A. G., Crystalline Silicon Solar Cells —

Advanced Surface Passivation and Analysis,

Sydney, Centre for Photovoltaic

Engineering, University of New South

Wales, ISBN 0 7334 0645 9, September,

1999, 340 pages.

C.B. Honsberg and S. G. Bowden, Photovoltaics:

Devices, Systems and Applications, Vol. 1, ISBN 0-

7334-0596-7, September, 1999.

M. A. Green, Power to the People, UNSW

Press, (in press).

Journal and Conference

PublicationsCotter, J.E. and Freedman, S., Speed of Light –

Virtual Solar Car Racing, Solar Progress, Vol.

20, No. 4, December 1999, p. 29.

Green, M.A. and Wenham, S.R., Photovoltaics

for the New Millennium, Conf. Record,

Australian Institute of Energy National

Conference, Melbourne, November, 1999,

pp44-52.

Honsberg, C. B., Multimedia Educational

Software in Photovoltaics, Solar Progress, Vol.

20, No. 4, December 1999, pp10-11.

Outhred, H. and Watt, M., Prospects for

Renewable Energy in the Restructured Australian

Electricity Industry, World Renewable Energy

Congress, Perth, W.A., 10-13 February 1999.

Watt, M. and Outhred, H., Australian and

International Renewable Energy Policy Initiatives,

World Renewable Energy Congress, Perth,

W.A., 10-13 February, 1999.

Watt, M. and Outhred, H., Implementing the

Renewable Energy Target, Outlook 99,

ABARE Conference, Canberra, A.C.T., 17-

18 March, 1999.

Watt, M. and Outhred, H., Review of Policy

Options for the Australian Renewable Energy

Industry, Solar 99, 37th ANZSES

Conference, Geelong, Vic, 1-3 Dec, 1999.

Wenham, S. R., Honsberg, C. B., Watt, M,

Green, M. A., Cotter, J., Largent, R., Silver,

M. D., Aberle, A. G., Spooner, T., and Cahill,

L., World’s First Bachelor of Engineering in

Photovoltaics and Solar Energy, 7th International

Symposium on Renewable Energy

Education, Oslo, (in press).

Wenham, S. R., Outhred, H., Jennings, P.,

Lee, P., New Undergraduate Engineering

Programs in Renewable Energy, 7th

International Symposium on Renewable

Energy Education, Oslo, (in press).

Wenham, S. R., Potential Role of Solar Energy

in the Next 20-50 Years, Energy for the

Future Conference, Australian Academy of

Technological Sciences and Engineering,

November 1999, 14 pages.

Wenham S.R., Aberle A.G., Photovoltaic tech-

nology at the University of New South Wales,

Workshop Proceedings, Workshop on

Renewable Energy, Perth, Australia, Feb.

1999, pp34-39.

Wenham, S. R., Education for Photovoltaics and

Solar Energy, Solar Progress, Vol. 20, No. 4,

December 1999, pp4-5.

Wenham S.R., Honsberg, C.B., Cotter, J.,

Largent, R., Aberle, A., Spooner, T. and

Green, M.A., Opportunities Arising Through

Rapid Growth of the Photovoltaic Industry, Tech.

Digest, 11th International Photovoltaic

Science and Engineering Conference,

Sapporo City, September, 1999, pp525-526.

Wenham, S.R., Honsberg, C.B., Cotter, J.,

Largent, R., Aberle, A.G., Spooner, T. and

Green, M.A., Australian Educational and

Research Opportunities Arising through Rapid

Growth of the Photovoltaic Industry, Solar

Energy Materials and Solar Cells, (in press).

Education Reports and

Non-Refereed PublicationsCotter, J.E., STA Final Report - Energy

Engineering Sub-Group – Renewable and

Photovoltaics Energy Conversion Technology,

Thailand-Australia Science and Engineering Project

Final Report, 1999, (19 pp.)

Honsberg, C., Progress in UNSW Photovoltaic

Educational Activities, prepared for presentation to

Georgia Institute of Technology, November

1999, 20 pages.

Largent, R., Contribution for Information and

Community Education Quarterly Report #1,

ACRE Project 7.4, April 1999.



ACRE Project 7.4, July 1999.



ACRE Project 7.4, October 1999.



ACRE Project 7.4, December 1999.

Wenham, S. R., Collaborative Agreement Report

for Renewable Energy Engineering Program, sub-

mitted to Dean of Engineering, Murdoch

University, July 1999, 8 pages.

Wenham, S. R., Proposed Renewable Energy

Engineering Program for Murdoch University,

submitted to Dean of Engineering,

Murdoch University, August 1999, 4 pages.

Wenham, S. R., Progress Report on New Degree

Development, submitted to Key Centre

Management Committee, UNSW and Dean

of Engineering, Murdoch University,

November 1999, 9 pages.

ResearchDue to commercial sensitivities associated

with industry funded collaborative research

programs, most of the published material

has been in the form of company reports

that are "commercial-in-confidence". Some

material however, usually associated with

the activities of PhD students working on

the respective projects, has been able to be

published in refereed journals.

Consequently, as listed below, all but one of

these publications have a PhD student as

the first listed author.

Refereed JournalsHonsberg, C.B., Cotter, J.E., Richards B.S.,

Pritchard, S.C., Wenham, S.R., Design

Strategies for Commercial Solar Cells Using the

Buried Contact Technology, IEEE Transaction

on Electron Devices, Vol 46 no. 10,

pp1984-1992, (1999).

Koschier, L.M., Wenham, S.R. and Green,

M.A., Modeling and Optimization of Thin-Film

Devices with Si1-xGex Alloys, IEEE Trans. on

Electron Devices, Vol. 46, pp2111-2115,

October, 1999.

Koschier, L.M., Wenham, S.R., Improved Voc

using Metal Mediated Epitaxial Growth in

Thyristor Structure Solar Cells, Progress in

Photovoltaics, (in press).

Nast, O. and Hartmann, A. J., Influence of

Interface and AI Structure on Layer Exchange

during Aluminium-Induced Crystallisation of

Amorphous Silicon", Journal of Applied

Physics (in press).

Nast, O. and Wenham, S. R., Elucidation of

the Layer Exchange Mechanism in the Formation

of Polycrystalline Silicon by Aluminium-Induced

Crystallisation, Journal of Applied Physics

(in press).

PublicationsPublications

0sF I N A N C I A L S

K39 �

institution, the University of

New South Wales. These funds

comprise 27.5% of the total

income and encompass support

for a range of Key Centre activ-

ities including the Centre

Director’s salary and the pro-

cessing laboratory upgrade to

satisfy new safety regulations.

A breakdown of the expenditure

of funding from the ARC Key

Centre’s Scheme is also provided.

Even though this source of

During 1999, an extensive budg-

etary reconciliation process was

necessary for the establishment

of the Key Centre as an inde-

pendent financial unit from the

School of Electrical Engin-

eering. The financial details

associated with this budgetary

reconciliation are provided in

the annual report for the Centre

for Photovoltaic Engineering.

income comprised only 15.7% of

the Key Centre’s total income,

few of the Key Centre’s activities

would have been feasible without

this important component. Of

this funding, 50% was spent on

salaries while 20% was spent on

equipment and 20% on consum-

ables for Key Centre operations.

The final 7.8% was spent on trav-

el, particularly in relation to the

establishment of collaborative

teaching programs with other

institutions and organisations.


� K38

The Key Centre for Photo-

voltaic Engineering was estab-

lished in January 1999 under the

Australian Research Council’s

Key Centres Scheme. The docu-

mentation and budget in the

original proposal for the Key

Centre indicated that no ARC

Key Centre funds would be used

to support the research projects

for the Key Centre. Instead, the

industry collaborative research

projects must all be self-funding

through industry and other

sources such as ARC SPIRT

grants. The total income for the

Key Centre in the year 1999 was

approximately $2m of which the

ARC Key Centre funds com-

prised 15.7%. This indicates the

success of the Key Centre in

attracting other sources of

income such as from industry

and teaching activities, therefore

maximising the impact of the

ARC funding.

The breakdown of Key Centre

income for 1999 according to

source is provided, with 17%

being earned from EFTSUs

through teaching activities. Also

from the University Operating

Grant is a research quantum

component of a further 13.3%.

Collaborative programs in

research and teaching facilitated

additional income from other

organisations such as the

Australian CRC for Renewable

Energy, Pacific Solar Pty Ltd,

BP Solar, Eurosolare and the

Sustainable Energy Devel-

opment Authority. Several other

industry sponsors have gener-

ously contributed to the

Sunsprint model solar car race

run by the Key Centre, con-

tributing a further 1.9% of the

Key Centre’s total income. With

regard to collaborative research

funding, one of the largest

sources has been the ARC

SPIRT Scheme, indicating the

quality and innovativeness of

the work being conducted. The

SPIRT Grants have contributed

a similar amount towards the

research of the Key Centre as

the Key Centre’s Scheme has

contributed to teaching activi-

ties. By far the largest single

income source for the Key

Centre has been from the host

FinancialsFinancials

ARC KEY CENTRE EXPENDITURETOTAL KEY CENTRE INCOME FROM ALL SOURCES - TOTAL $1,940,666.

Documents

Centre Special Research Photovoltaics 1999...Photovoltaics Special Research Centre finishing at the end of1999, the group was successful in obtain-ing support for a new ARC Special