Graphene Nanoribbons

Xiaolin Li, et al., Science, 2008.

Unzipping of Nanotubes

Self-Oriented Vertical Single-Walled NTs

~600 ºCplasma

CxHy catalyst

Furnace

500 - 1000°C

CH4 ? C+ H2

600 °C

plasma

Base

growth

CH4 ? C+ H2

600 °C

CH4 ? C+ H2

600 °C

plasma

Base

growth

CVD PECVD

Yuegang Zhang, Yiming Li, J. Phys. Chem, 1999;

CxHy

Suspended Nanotubes

Nanotube powerline

Nanotube square

TEM: Single-Walled

NT

Alan Cassell, Nathan Franklin, JACS, Adv. Mat., 1999-2000

Self-Oriented Vertical Multi-Walled NTs

Shoushan Fan, Nathan Franklin, et. al., Science, 1999.

CVD

pattern individual “seeds” grow 1 tube per “seed”

SWNTs Synthesis From Individual Nanoparticles

100 nm

2nm Fe seed

250 nm

CVD

300 nm

Ali Javey, JACS, 2005

Electromechanical Properties of Suspended Nanotubes

SiO2

n+ Si

S D

Z0

Thomas Tombler, Chongwu Zhou, et al., Nature, 2000;

Jien Cao, et al., PRL, 2004.

Suspended Nanotubes:

Very High Quality & Unperturbed

p-doped Si

SiO2

VGB

Si3N4

S D

VGL

Mo, W or

Pt

As-grown between Pt across trenches

Exhibit ‘clean’ quantum transport signatures.

nanotube on substrate

suspended over trench

SiO2

Si3N4

nanotubePt

Pt gate

SiO2

Si3N4

nanotubePt

Pt gate

2 μm

Pt

Non-Equilibrium Hot Phonons in

Suspended Tubes

Negative differential conductance (NDC) & hot phonons

Eric Pop, David Mann et al., PRL, 2005

Quantum Transport (Aharonov Bohm Effect)

2.5

2.0

G (

e2

/h)

-2.0 -1.5 -1.0Vg (V)

B=0 T

B=8 T

T=0.3K

Jien Cao et al, PRL, 2004; Nature Materials, 2005

B

e-

e- B Field

‘Good’ Contacts

Multi-Turn FP Interference

‘Less Good’

Contacts

Shells of

single-e’s

split

& cross

in B Field

nanotube

High- Dielectrics, Ohmic Contacts and Channel

Scaling

0.3 m

D

S

D

3 m

50 m

(Pd)

(Pd)

(Pd)

D

D

S

a

Ali Javey

Jing Guo, Mark Lundstrom,

Paul McIntyre,

Damon Farmer, Roy Gordon

Nature Materials, 2002; Nature 2003; Nano Lett., 2004;

Pushing the Limit of Nanotubes Field Effect Transistors

(FETs)

50 nm

S

D

Gate

HfO2 (2-8nm

SWNT

CNTs are advanced electronic materials owing to:

• Strong bonding (high current carrying; High phonon energy)

• Stable and inert surfaces