LED: Critical Research Issues · ©2006 Philips Lumileds Lighting Company. AB08 . C.Wetzel Future Chips Constellation Composite White Light Emitting Diode blue plus phosphor rel

Future Chips ConstellationRensselaer

CW 2012- 6- 1C. Wetzel

January 30, 2013

Future Chips Constellation, Department of Physics, Applied Physics and Astronomy

Rensselaer Polytechnic Institute, Troy, NY, USA

LED: Critical Research Issues

DOE Solid State Lighting R&D Workshop Long Beach, CA

Christian Wetzel and Theeradetch Detchprohm

Future Chips ConstellationRensselaer

CW 2011-04 18 C.Wetzel

This work is supported by a United States of America DOE/NETL Solid-State Lighting Contract of Directed Research under DE-EE0000627. This work is also supported by the NSF under cooperative agreement EEC-0812056 and by New York State under NYSTAR contract C090145.

Future Chips Constellation Rensselaer

CW 2012-10-14 1951.c C.Wetzel

Future Chips ConstellationC. Wetzel

Materials Development Needs

• Droop Reduction => Higher Efficiency

=> Higher Lumen => Less Cooling

• Integration LED + Phosphor => Direct Spectrum LED

• Integration LED + Driver + Sensor + Controls => AC LED System

Rensselaer CW 2012-06-09 1138.c


New Ideas on How to Avoid Droop

New ideas — need to be tested



GaN on Nano-Patterned Sapphire

profound change in defect structure

reference LED LED on nanopatterned substrate

8 -2

Epitaxy on Large Surface Miscut – Built-In Patterning the art of light extraction

Entire LEDs in GaN substrate miscut (deg)fish scale pattern

0.06° GaN 0.70° GaN

Su

bst

rate

Ga

N L

ED

C.J.M. Stark et al. Appl. Phys. Lett. 101, 232106 (2012), dx.doi.org/10.1063/1.4769442

2.24° GaN 0.25° Sapphire

LED surface image

Future Chips ConstellationC. Wetzel Rensselaer

CW 2012-06-09 1138.c


Droop Reduction

Bulk GaN homoepitaxy

New QWs new profile

new alloy

Semipolar substrate

epitaxy

Nano-patterned Si substrate

new substrates

2.24° GaN

C.J.M. Stark et al. Appl. Phys. Lett. 101, 232106 (2012)


Sapphire

cTD

500 nm

GaN

g=(0002)

stacking faults

Yufeng Li, et al. Appl. Phys. Lett, 98(15), 151102 (2011)


The Green Gap

after: S. DenBaars, LS-13 Intern. Symp. Science Technology Lighting, June 2012, Troy NY

Y. Li et al Appl. Phys. Lett. 98, 151102 (2011)

RPI

window of opportunity


Future Chips ConstellationC.Wetzel

Composite White Light Emitting Diode

blue plus phosphor

rel.

Inte

nsity

blue LED

solar spectrum

p031407a.o

p020309a.c

T = 6500 K

eye stimulus functions

400 500 600 700 Wavelength (nm)

blue green red

11

00

0

10k

6k

4k

3k 2k

1k

1931 Chromaticity Diagram400 500 600 700 Wavelength (nm)


fox consulting ClipArtOf.com

©2006 Philips Lumileds Lighting Company. AB08

http:ClipArtOf.com



blue plus phosphor

rel.

Inte

nsity

blue LED

+ phosphor

solar spectrum

p031407a.o

p020309a.c

T = 6500 K


400 500 600 700 Wavelength (nm)

blue green red

11

00

0

10k

6k

4k

3k 2k

1k

1931 Chromaticity Diagram400 500 600 700 Wavelength (nm)


fox consulting ClipArtOf.com

©2006 Philips Lumileds Lighting Company. AB08

http:ClipArtOf.com


Proper Placement of Phosphor Layer

index and thermal matching

Index of PropagationTemperature LED refraction time

n zz + z

_

Phosphor

Useful

flux

sandwiched phosphor — too hot of for standard phosphor


schematic





z z n zz+

_

Phosphor

Useful flux


remote phosphor — high light coupling losses

schematic





z z n zz+

_ Phosphor

Useful

flux

phosphor in source — highest possible flux need epi compatible


schematic


RGB LED

10k

6k

4k

3k 2k

1k

1931 Chromaticity Diagram0


blue green red

0

1

rel.

Inte

nsity

solar spectrum

0

1

400 500 600 700 Wavelength (nm)

T = 6500 K

human eye

visible

schematic

CW

_2011-0

8-1

9_1938.c

400 500 600 700 Wavelength (nm)

emc.cmich.edu/sunsafety ClipArtOf.com Rensselaer Future Chips ConstellationC.Wetzel Rensselaer Future Chips ConstellationC.Wetzel

CW 2012-06-09 1138.c

http:ClipArtOf.com


RGBY LED

400 500 600 700 0


blue green red

1931 Chromaticity Diagram

0

1

rel.

Inte

nsity

solar spectrum

0

1

400 500 600 700 Wavelength (nm)

T = 6500 K

human eye

visible

schematic

CW

_2011-0

8-1

9_1938.c

Wavelength (nm)

emc.cmich.edu/sunsafety ClipArtOf.com Rensselaer Future Chips ConstellationC.Wetzel Rensselaer Future Chips ConstellationC.Wetzel

CW 2012-06-09 1138.c

http:ClipArtOf.com


Direct Spectrum LED

keep it semiconductor

Green, Yellow Red rare earth free phosphor free index matched InGaN or some new alloy

Individual RGBY semipolar bulk GaN-based

Multicolored RGBY microstructured nanostructured

0

1

rel.

Inte

nsity

solar spectrum

0

1

400 500 600 700 Wavelength (nm)

T = 6500 K

human eye

visible

schematic

CW

_2

011

-08

-19

_1

93

8 c



Luxeon White LED

epi - chip - lamp

Chip

Epi

Flip chip - style

Lamp



Periphery

old world technology

www.biztrademarket.com

+ Driver + Cooling

... an awkward BOM (Bill of Materials)


CREE


Standard Bulb Replacement fits the socket

Soraa

MR-16 PAR-38 A19

sipilPh



Nostalgia or Progress to Quality of Life?

as seen where people are

boutique or

trendsetter?

Published: Friday, October 26, 2012

The Charles F. Lucas Confectionery & Wine Bar Troy, NY



Complete Integration on the Materials Level

the better way to go

Integrated driver + sensor

logic _

_S G D +GaN-based Heterostructure

any substrate

LED Transistor Capacitor


schematic


High Voltage LED, AC LED

daisy chaining

+

_

+

_

+

_

Why not 60 V?LED LED LED110 V?

240 V?


schematic



daisy chaining

Tunnel Tunnel

Junction Junction

+

_


240 V?


schematic



daisy chaining

Reversible Reversible Tunnel Tunnel

Junction Junction

~ ~


240 V?


schematic


The New Bulb

the way you gonna know it

LED LED LED


schematic


AC LED System

• Convergence • Integration

– LED + FET, – Monolithic

– FET + Capacitor – Epitaxial

– Sensors + Logic – Same Materials +

_

CW

_2 0

12

-10

-14 _

04

22

.c


_+ S G DMOVPE GaN-based

Heterostructure

Defect reduced HVPE template

LED Capacitor Transistor


Materials Development Needs

• Droop Reduction => Higher Efficiency

=> Higher Lumen Yufeng Li, et al.

Appl. Phys. Lett, 98(15), 151102 (2011)=> Less Cooling

• Integration LED + Phosphor => Direct Spectrum LED

Integration LED + Driver + Sensor + Controls

+•

_ _=> AC LED System + S G D

Sapphire

c

voids

TD

500 nm

GaN

g (0002)

stacking faults

0

1

rel

nten

sity

solar spectrum

0

1

400 500 600 700 Wavelength (nm)

T = 6500 K

human eye

visible

schematic

CW

_2

011

-08

-19

_1

93

8.c


10th International Conference on Nitride Semiconductors

Christian Wetzel Jaime A. Freitas, Jr.

Washington DC, USA Asif Khan – Honorary ChairAugust 25-30, 2013

www.icns10.org expected attendance: >1000

- Bulk Crystal Growth - Epitaxial Growth - Optical and Electronic Properties - Processing and Fabrication - Defect Characterization and Engineering - Structural Analysis - Theory and Simulation - Nanostructures - Light Emitting Devices - Electron Transport Devices - Photovoltaics and Energy Harvesting - New Materials and New Device Concepts

http:www.icns10.org

LED: Critical Research IssuesMaterials Development NeedsNew Ideas on How to Avoid DroopDroop ReductionThe Green GapComposite White Light Emitting DiodeProper Placement of Phosphor LayerComposite White Light Emitting DiodeDirect Spectrum LEDLuxeon White LEDPeripheryStandard Bulb ReplacementNostalgia or Progress to Quality of Life?Complete Integration on the Materials LevelHigh Voltage LED, AC LEDThe New BulbAC LED System

Documents

LED: Critical Research Issues · ©2006 Philips Lumileds Lighting Company. AB08 . C.Wetzel Future Chips Constellation Composite White Light Emitting Diode blue plus phosphor rel