Fabrication & Characterization of 1D
Solid-State Model Systems on Silicon
FONDS NATIONAL SUISSE
SCHWEIZERISCHE NATIONALFONDS
FONDO NAZIONALE SVIZZERO
SWISS NATIONAL SCIENCE FOUNDATION
FN NFS
François Bianco
Fabrication & Characterization of 1D
Nanolines on Silicon
FONDS NATIONAL SUISSE
SCHWEIZERISCHE NATIONALFONDS
FONDO NAZIONALE SVIZZERO
SWISS NATIONAL SCIENCE FOUNDATION
FN NFS
François Bianco
Motivations
Time
Moore's Conjecture
"The number of transistors incorporated in a chip will approximately double every 24 months." Gordon Moore, Intel co-founder
108
104
106
Nu
mb
er
of
tra
ns
isto
rs
Time
Moore's Conjecture
"The number of transistors incorporated in a chip will approximately double every 24 months." Gordon Moore, Intel co-founder
108
104
106
Nu
mb
er
of
tra
ns
isto
rs
Pictures, CC-BY-SA Wikipedia contributors
1980 2010
Size Limit
mm ŵmø h
air
s
nm
1947 2012
© Intel newsroom 3D transistor & Nature Nanotechnology 7, 242 (2012)
cells
Size Limit
mm ŵmø h
air
s
nm
1947 2012
© Intel newsroom 3D transistor & Nature Nanotechnology 7, 242 (2012)
cells
"What would happen if we could arrange the atoms one by one the way we want them?" Richard Feynman
Chain, CC-BY BotheredByBees (Flickr)
Atom Chainsor nanolines/nanowires
Nanowire's Applications
Nature Photonics 7, 306 (2013)Adv. Mater. (2013)
Adv. Mater. 15, 997 (2003)
Angew. Chem. 120, 4597 (2008)
APL 85, 6389 (2004)
Nature Nanotechnol. 2, 626 (2007)
Nature Nanotechnol. 7, 242 (2012)
Memory
Single-atom transistor
Solar cell
Gas detector
Catalyst
Vertical nanowires, © EPFL Press
Nature Biotechnol. 23, 1294 (2005)
Proteins detector
Open Questions
Fabrication? Properties?
Lego bricks, CC-BY-SA dbesham (Flickr)
Presentation Outline
Physics in One Dimension ?
Measurement & Synthesis of Nanolines
Nanolines on Silicon:
Bi nanolines Haiku stripes Haiku Dangling
Bond Rows
Physics in One
Dimension
One-dimensional CC-BY-NC-ND (with permission) Andredoreto (Flickr)
One Dimension
Trac Jam,, CC-BY-SA Andreas (Flickr)
1D Physics
CC-BY-NC-ND (with permissions) Water drop, Beauty Eye & Pipes, e.asphyx (Flickr)
Fermi Liquid Tomonaga-Luttinger Liquid
2D 1D
Quasiparticles Collective excitations
1D Physics
CC-BY-NC-ND (with permissions) Water drop, Beauty Eye & Pipes, e.asphyx (Flickr)
Fermi Liquid Tomonaga-Luttinger Liquid
2D 1D
Quasiparticles Collective excitations
Spin-charge separation
Power laws
Peierls distortion
Predictions:
a
2a
Peierls Distortion
En
erg
ie
EF
-π/2a π/2a
En
erg
ie
EF
-π/2a π/2a
Wavevector
Wavevector
Insulator
Metallic
Peierls Distortion Example
293 K
(20°C)
4.7 K
(-268°C)
Insulator
Platinium on Ge(001)
Surf. Sci. 602, 1731 (2008)
Metallic
Can We See
Nanostructures?
Scanning Pr e
Braille, CC-BY-SA kainita (Flickr)
IFeedback
Scanning tunneling microscope(STM)
2 nm
Monohydride Silicon (001)
Scanning Probe
IFeedback
Scanning tunneling microscope(STM)
STM Laboratory
Low Temperature
77 K (196°C)
Ultra-High Vacuum
(UHV, ~ 5×10-11 mbar)
Nanolines
S nt es s
❚❤e ❯n✐✈ersa❧ ▲a❜e❧✱ ❈❈✲❇❨✲N❈ ❘an❞a❧❧ ▼unroe ✭❳❑❈❉ n➦✶✶✷✸✮
Fabrication Methods
Top-down
(Lithography)
Fabrication Methods
Top-down
(Lithography)
Bottom-up
(Self-assembly)
❱icinal Surfaces
Stairs, courtesy Sylvain Masson (Flickr)
Vici♥al Surfaces
❙tairs, courtes② ❙②l�ai✁ Masso✁ (❋lic❦r)
Co o✂ ✄ici✂al Cu(111)
P☎✆ ✽7, 16✹06(☎) (✝01✞)
2 nm
dimer row
[110]
[110]
Buckled c(4×2)
Flip-flop (2×1)
Silicon (001)
Buckled c(4×2)
Flip-flop (2×1)
Sid
e v
iew
To
p v
iew
Sid
e v
iew
To
p v
iew
Synthesis Principle
Synthesis Principle
Seeds, CC-BY-NC-SA CIMMYT (Flickr)
Synthesis Principle
Seeds, CC-BY-NC-SA CIMMYT (Flickr)
Bismuth
Bismuth, Free Art Alchemist-hp (Wikipedia)
Synthesis Principle
Seeds, CC-BY-NC-SA CIMMYT (Flickr)
Bismuth
Bismuth, Free Art Alchemist-hp (Wikipedia)
Rows of Red, CC-BY-NC-ND (with permission) sea turtle (Flickr)
580°C
Bismut
Nano nes
Con tant Width
✺ n♠ 2 n♠
4 ✟i di✠❡r✡ wid❡☛o✉☞✌❡ ❝hain o❢ ✍i di✠❡r✡
Tunable Density
20 nmLow High
Micro✎eters Long
1 μm 50 nm
❩oo✏
sid
e v
iew
top
vie
w
Haiku Structure
BiBi
5
75
7
5
J.H.G Owen et al. J. Mater. Sci. 41, 4568 (2006)
Si
Bi-Nanolines Advantages
Self-assembled
Micrometers long
Tunable density
Potential template
Well know structure
On a semiconductor
Flat surface
Fixed width
Haiku Stripes
Appl. Phys. Lett. 97, 093102 (2010)
& Phys. Rev. B 84, 35328 (2011)
Synthesis
Hydrogenation
380°C
sid
e v
iew
2 nm
✑onoh✒✓ri✓e Silicon
H H H H
10 nm 1 nm
Haiku Stripes
Hai✔u ✕tripe ✖o✗✘✙
✚i✚i
✛ i
✜ e ✢
iew
5
75
7
5 ✣i
Haiku Stripe Model
✤ i
✥ e ✦
iew
5
75
7
5
HH H H H
H
Si
Haiku Stripe Model
sid
e v
iew
5
75
7
5
HH H H H
H
Si
Field, CC-BY-SA skrewtape (Flickr)
Haiku Stripe Model
sid
e v
iew
5
75
7
5
HH H H H
H
Si
Field, CC-BY-SA skrewtape (Flickr) Bulbs, CC-BY-SA, brewbooks (Flickr)
How can we be sure that itis a silicon only structure?
X-Ray Photospectroscopy
EγX-ray
e-Ekin
Spectrometer
Ekin
Eγ
Core levels
Valence band
Φ
e-
Binding energy
(XPS)
X-Ray Photospectroscopy
Binding energy [eV]
[Ele
ctr
on
co
un
ts/s
]
O C B O
Si Si
Si
Si
Si
Clean Si monocrystal
X-Ray Photospectroscopy
Binding energy [eV]
[Ele
ctr
on
co
un
ts/s
]
O C B O
Si Si
Si
Si
Si
Clean Si monocrystal
Bi
Bi
Bi
Bi
Bi-exposed sample before H exposure
Bi
X-Ray Photospectroscopy
Binding energy [eV]
[Ele
ctr
on
co
un
ts/s
]
O C B O
Si Si
Si
Si
Si
Clean Si monocrystal
Bi
Bi
Bi
Bi
Bi-exposed sample before H exposure
Bi
Bi-exposed sample after H exposure
X-Ray Photospectroscopy
Binding energy [eV]
[Ele
ctr
on
co
un
ts/s
]
O C B O
Si Si
Si
Si
Si
Clean Si monocrystal
Bi
Bi
Bi
Bi
Bi-exposed sample before H exposure
Bi
Bi-exposed sample after H exposure
STM SimulationsIn collaboration with Prof. D. Bowler UCL & LCN
Relaxed structure
STM simulation
Charges densities
1 nm
Filled States
simulation
experiment
High current(200 pA)
simulation
experiment
Low current(80 pA)
simulation
experiment
Cross Section
1.54 nm
70
pm
5 pm
He
igh
t
Width
simulation
oset -10 pm
experiment
1 nm
Empty States
+2.5 V
Simulations+ 2.5 eV
Data
Empty States
+2.5 V
Simulations+ 2.5 eV
Data
3 nm
+2.0 V
1 nm
+ 1.0 eV
Charge Densities
3 nm
Sid
e v
iew
What else?
Air Resistant
Exposed to air for 25 min
3 nm
Micrometer Long
200 nm 50 nm
Self-assembled
Stable to 400°C
(in UHV)
Micrometer long
Properties Summary
Tunable density
Inert in air
Self-assembled
Stable to 400°C
(in UHV)
Micrometer long
Properties Summary
Tunable density
Inert in air
Delocalized
electronic state Perfectly matching
model
Self-assembled
Stable to 400°C
(in UHV)
Micrometer long
Properties Summary
Tunable density
Inert in air
Delocalized
electronic state Perfectly matching
model
Contacting
Probing 1D physics&
What about Physics?
ContactingE
lectro
de
Clamp
Silic
on
1 mm
Mask deposition
20 nm
Markers & Contacts
APL 100, 103103 (2012)
Au markers
Gold depositionExample
Optical measurement
Doping
Spectroscopy
I(+1.5 V)
What about Physics?
2 nm
Outlook:
1D Dan l n
Bon s Rows
❆✧★ ◆ano (2013)
Hydrog✩nation
42✵✪✫
Synthesis
Assemb✬y Interests
Molecular molds
Atom assembly
Annu. Rev. Phys. Chem. 60, 193 (2009)
PRL 91, 136104 (2003)
Gallium
Phosphine
Both examples were
sequentially made
Haiku DB ✯ows
H H
π* πsid
e v
iew
HydrogenatedSi dimer
Dangling
Bond (DB)
10 n
H✰B Rehydrogenated
Central Dimer Model✳3
D v
iew
Sid
e v
iew
HH H
H
Buckled Flat
HH H
H
H Binding Energy
H atom on Si(001)
4.37 eV
+0
.16
+0
.13
-0.1
0
-0.1
5
+
-
More stable
Less stable
EB
/ H
[e
V]
sid
e v
iew
HH H
H
Buckled Flat
HH H
H
-0.1
5
+0
.13
-0.1
0
+0
.16
From DFT calculations
Missing Hydrogen
6% Si terraces
% of dehydrogenated Si atoms
Missing Hydrogen
6% Si terraces
% of dehydrogenated Si atoms
85
% Haiku stripe
Alternating Flat Dimers
+ 1.8 V - 1.8 V
Alternating Flat Dimers
+ 1.8 V - 1.8 V
Spin-polarized structure?
Test at room temperature
Outlook:
Properties Summary
Micrometer long
Highly reactive template
Self-assembled
Known structure
Properties Summary
Micrometer long
Highly reactive template
Self-assembled
Known structure
Assembling 1D molecular or atomic chains
Con l s on
✴✻mmary
Self-assembly
Lego bricks, CC-BY-SA dbesham (Flickr)
Haiku stripes Haiku DB rows
Bismuth nanolines
Summary
Haiku stripes Haiku DB rows
FONDS NATIONAL SUISSE
SCHWEIZERISCHE NATIONALFONDS
FONDO NAZIONALE SVIZZERO
SWISS NATIONAL SCIENCE FOUNDATION
FN NFS
✼✾anks
& ❏❛✿❀s ❁●❁ ❖we❂ ❃❄❣❅❊❂ ❍❁ ■öster
◗❲oup photo, ➞ ❬❭ ❪❫❴❵❥♦s
"Atomic hashi.A pair of Bismuth dimers,On Silicon core.
Remove all Bismuth,Silicon in silicon.Atomic template."
James H.G. Owen
5
75
7
5
HH H H H
H
Si