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