1

Experimental and Molecular Dynamics Studies Related with Carbon Nanotubes

Experimental and Molecular Dynamics Studies Related with Carbon Nanotubes

Shigeo Maruyama

Dept. of Mech. Eng., The University of Tokyohttp://www.photon.t.u-tokyo.ac.jp/~maruyama/

E-mail: maruyama@photon.t.u-tokyo.ac.jp

Colloquium Micro/Nano Thermal Engineering @ Seoul, 2002/2/18

(a) C60 (c) La@C82(b) C70

(e) SWNT (f) MWNT

C60

PVWin

(d) Sc2@C84

Typical Structures of Fullerene & NanotubesTypical Structures of Fullerene & Nanotubes

What is Carbon Nanotube?What is Carbon Nanotube?

Chirality and Radius of SWNTChirality and Radius of SWNT

(10,10)Armchair

(10,0) Zigzag (10,5) Chiral

a1

a2

http://vortex.tn.tudelft.nl/~dekker/nanotubes.html

STM Image of Individual AtomsSTM Image of Individual Atoms TEM Pictures of SWNT RopesTEM Pictures of SWNT Ropes

Individual tube diameter: 1.3 nmSpacing: 0.34 nmMisalignments and Terminations

TEM from Smalley et al. at Rice University

About 100 SWNTs

2

R. E. Smalley at Rice University

Bucky Paper (A Tangle of Ropes)Bucky Paper (A Tangle of Ropes)

Discovery of MWNT: Iijima (1991)

Discovery of SWNT (Co-Fe): Iijima(1993)

MWNT by CVD

Macroscopic Prod. SWNTs (Ni-Co): Smalley (1996)

Arc Production (Ni-Y): Journet et al. (1997)

SWNT by CVD catalytic growth from metal particle

Field Emission, AFM Tip, Hydrogen Adsorption

Discovery of Carbon NanotubesDiscovery of Carbon Nanotubes

Tips of AFM

Field Emission

Applications of NanotubesApplications of Nanotubes

Fuel Cell Electrode

FET BiosensorNanowires

H2 StorageMechanical

Generation of SWNTsGeneration of SWNTs

Laser-Oven SWNT GeneratorLaser-Oven SWNT Generator

Electric Furnace

Nd:YAG Laser

Manometer

Quarz Lens (f=1200mm)

Quartz Tube

LeakAr Flow

StopperQuartzWindow

Mo Rod

Target Rod

Holder

Vacuum pump

Pirani Meter

RotaionFeed-through

Laser-Oven Nanotube GeneratorLaser-Oven Nanotube Generator

TEM from Smalley et al. at Rice University100 200Ramam Shift (cm–1)

Inte

nsity

1.20nm

1.47nm

1.32nm

532 nm 53 %

532 nm 26 %

532 nm 1 %

3

He gas

Power(+) Power(-)

Window

Graphite Electrodes

CCDCamera

Reflector

Stepping motor

Vacuum pump

Arc-Discharge Generator

SEM Image of PurificationSEM Image of Purification

600nm600nm

Original Purified

Amorphous Carbon Bundle of Tubes

Catalytic CVD Generation of SWNTsCatalytic CVD Generation of SWNTs

Self-Oriented Arrays of MWCNTs by CCVD(H. Dai’s Group at Stanford)

Self-Oriented Arrays of MWCNTs by CCVD(H. Dai’s Group at Stanford)

CCVD (Catalytic Chemical Vapor Deposition)CCVD (Catalytic Chemical Vapor Deposition)

MgO supported Metal

1000 °C, methane

TEM Raman

J.-F. Colomer, C. Stephan, S. Lefrant, G. V. Tendeloo, I.Willems, Z. Konya, A. Fonseca, Ch. Laurent, J. B. Nagy

CPL (2000)

J.-F. Colomer, C. Stephan, S. Lefrant, G. V. Tendeloo, I.Willems, Z. Konya, A. Fonseca, Ch. Laurent, J. B. Nagy

CPL (2000)

Single walled carbon nanotubes (swnt)from Hi pressure CO ( Pco)

R. E. SmalleyCNLRice University

1 step

Gas phase

$500/gram

The HiPco ProcessThe HiPco Process

4

New Catalytic CVD Generation of SWNTsNew Catalytic CVD

Generation of SWNTs

Experimental TechniqueExperimental Technique

2.5/2.5 : Fe:Co (wt%) on Zeolite 30mg

C source vacuum

Electric Furnace

(CH3CO2)2Fe(CH3CO2)2Co-4H2O

Catalysts Supports

Zeolite USYHSZ-390HUA

SiO2 99.6 wt%Al2O3 0.4wt%SiO2/Al2O3: 390.0

300nm

SEM Image SEM Image

50nm

TEM Image TEM Image

10nm

TEM ImageTEM Image

0 500 1000 1500

100 200 300 400

2 1 0.9 0.8 0.7

Raman Shift (cm–1)

Inte

nsity

(arb

. uni

ts)

Raman Shift (cm–1)

Diameter (nm)Raman Spectra

(488nm)Raman Spectra

(488nm)

)(248)( 1−=cm

nmdω

Laser vaporization conditionRod Ni/Co 0.6 at.% Ar gas 50sccmTemperature 1130℃　

laser

CCVD 800

5

Temperature DependenceTemperature Dependence

1200 1400 1600

Inte

nsity

(arb

.uni

ts)

Raman Shift (cm–1)100 200 300 400

2 1 0.9 0.8 0.7

Inte

nsity

(arb

.uni

ts)

Raman Shift (cm–1)

Diameter (nm)

600

650

700

800

Laser 1130

1.22nm 1.02nm 0.96nm 0.83nm

BWFD band G band

Generation mechanism of SWNTsGeneration mechanism of SWNTs

Model by Yudasaka et al., JPC B (1999)Model by Yudasaka et al., JPC B (1999)

Model by Kataura et al., Carbon (2000)Model by Kataura et al., Carbon (2000)

H. Kataura , Y. Kumazawa , Y. Maniwa , Y. Ohtsuka , R. Sen , S. Suzuki ,Y. Achiba, Carbon 38 (2000) 1691-1697.

D S Ra c d

R R

e e= = = == = = == =

−6 325 129 15 13150 80469 0 011304 19 2 517 2 0

1

0 0 0

1 2

. eV . . & . &

. . .. & . &

βδ

A A

A A

Potential parameters

From D. W. Brenner: Phys. Rev. B, 42, 9458(1990)

1f

r0

R1 R2

Cut-off function

k

i j

qijk

C-C Potential FunctionC-C Potential Function

{ }∑∑<

−=i ij

ijAijijRb rVBrVE)(

* )()(

{ })(2exp1

)()( ee

R RrSSDrfrV −−−

= β

−−−

= )(2exp1

)()( ee

A RrSS

SDrfrV β

{ }δ

θ−

≠

+=

+= ∑

),(

* )()(1,2 jik

ikijkcijjiij

ij rfGBBB

B

++−+=

220

20

20

20

0 )cos1(1)(

θθ

dc

dcaGc

Total Energy Eb:

M-C and M-M Potential Function ExpressionM-C and M-M Potential Function Expression

CARij VVVE ++=VR: Repulsive term VA: Attractive term

VC: Coulomb term

N C: carbon coordinate number

B*: normalized bond order

cM, cC : charge of M (+) and C(-)

f(rij) : cut-off function

{ })(2exp1

)( eije

ijR RrSSDrfV −−−

= β { })(/2exp1

)( *eij

eijA RrS

SSDBrfV −−−

⋅−= β

ijijC r

ccerfV MC

0

2

4)(πε

−=

∑≠

+=)(carbon

C )(1jk

ikrfN

{ }δ)1(1 C* −+= NbB

)exp(3 2C

1M kNkc +−−= CMC / Ncc =

∑≠

+=)( metal

M )(1jk

iki rfN2

MMji

ijNNN +

=

{ })1(exp)( 21 −−+= ijDeeije NCDDND

{ })1(exp)( 21 −−−= ijReeije NCRRNR

M-C M-M

N Mi: metal coordinate number

ij

jiijC r

ccerfV MM

0

2

4)(πε

=

6

Snapshots of Clustering Process at 6000 psSnapshots of Clustering Process at 6000 ps2500 carbon atoms & 25 Ni atoms

Control temperature Tc = 3000 K, 585Å Cubic Box

Snapshots of Annealing Processfor NiC60

Snapshots of Annealing Processfor NiC60

Cluster Source Nozzle for FT-ICR

Pulsed Valve

Target Disk

Waiting Room

Focused Laser Beam

He 10 atm

Expansion Cone

Cluster Beam

FT-ICR (Fourier Transform Ion Cyclotron Resonance)Mass Spectrometer

Turbopump

Gate Valve

Cluster Source

6 Tesla Superconducting Magnet

100 cm

DecelerationTube

Front Door

Screen Door

Rear Door

Excite & DetectionCylinder

ElectricalFeedthroughGas Addition

Ionization Laser

Probe Laser

Negative ClustersNegative Clusters

70 80Number of Carbon Atoms

Inte

nsity

(arb

itrar

y)

716 718 720 722 724

Mass (amu)

Inte

nsity

C60– + C60H

–

NiC50– + CoC50

– + NiCoC45–

FT–ICR Signal

Isotope Analysis

Isotope DistributionIsotope Distribution

35%C50NiCo

40%C55Ni

40%C55Co

50%C60H

100%C60

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The Way to Nanotube? The Way to Nanotube?

3000K

Collisions 2000K Slower Rate of Shrinking

2000K

Enlarged View

Generation Model of SWNTsGeneration Model of SWNTs

Electric Furnace

Ni/Co LoadedGraphite

Evaporation~ 1.7 µg/pluse

Ar flow0.8 cm/s, 500 Torr

YAG Pulse

Block

Block

200~500µs2cm

3ms~1s

Molecular Dynamics Simulations Related to SWNTsMolecular Dynamics Simulations Related to SWNTs Fuel Cell and Hydrogen StorageFuel Cell and Hydrogen Storage

FUEL CELLS(PEFC) Distributed power supply

AutomobilesMobile machines

Supply of hydrogenStorage problems for small light-weighted fuel cells

Liquid hydrogenHigh pressure gasMetal hydrideCarbon materials

Methanol Regenerator is heavy

Low temperature, Energy loss

Weight of case

Heavy

A. C. Dillon et al., Nature, 386, (1997)

Energy Density of HydrogenEnergy Density of Hydrogen Initial Configuration for (10,10) SWNTsInitial Configuration for (10,10) SWNTs

10 x 3.45 x 20 nm box

9504 Hydrogen Molecules

7 SWNTs Bundle (440 C atoms each)

3080 C atoms

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Snapshots of Absorption for (10,10) SWNTsSnapshots of Absorption for (10,10) SWNTs

Initial 12 MPa

Transformα = 0.05 α = 1

Phase TransformationPhase Transformation

(a) 12 MPa (b) Transformed

(c) 6 MPa (d) Transformed

0 102

4

6

8

Gra

vim

etry

Ene

rgy

Den

sity

[wt%

]

Pressure [MPa]

(a)

(b)

(c)

(d)

Snapshots for Various SWNTsSnapshots for Various SWNTs

(10,10) (16,16)

ClosePacked

InterstitiallyFilled

6.1 wt %

7.5 wt %

7.2 wt %

8.6 wt %

Heat ConductionHeat Conduction

Measurement of an Isolated MWNTMeasurement of an Isolated MWNT

P. Kim, L. Shi, A. Majumdar, P. L. McEuen, Thermal Transport Measurements of Individual Multiwalled Nanotubes, Los Alamos Natl. Lab.,

Prepr. Arch., Condens. Matter (2001), 1. PRL 87, 215502-1 (2001)

100 µm 1 µm

Simulation TechniqueSimulation Technique

y290K 310K

202nm0.7nm

290K 310Ky

(Diamond)2230K

/,6

,/2

)(

D =

==∆=

−+=

θ

θωωπ

αα

ασ

h

&&&

DBDDSCB

RandPot

kmtTkσ

m xffx

Temperature Control by Phantom Technique

Without the Periodic Boundary Condition!!

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Temperature Distribution along a NanotubeTemperature Distribution along a Nanotube

–1000 0 1000290

300

310

Position (Å)

Tem

pera

ture

(K)

64.5 K/µm

phantom (290K)

phantom (310K)

q = 25.0 GW/m2

Thermal ConductivityBetter than Diamond?

Effect of nanotube lengthEffect of nanotube length

300K

Ring Area of 3.4 Å102 103100

200

300

400

500

600700

Length of nanotube L (Å)

Ther

mal

con

duct

ivity

λ (W

/mK)

(5,5)

(10,10)

λ=a L0.32

(8,8)

λ=a L0.21

λ=a L0.06

Phonon Dispersion Relations (5,5)-101nmPhonon Dispersion Relations (5,5)-101nm

0 0.5 1.0

10

20

30

40

50

60

Wave vector k (1/Å )

Fre

quency

(TH

z)

0 0.5 1.0 0 0.5 1.0

cca −3π

r θ z

0

1000

2000

ν/c

(cm

–1)

vz

aa

Phonon Dispersion Relations (5,5)-101nmPhonon Dispersion Relations (5,5)-101nm

0 0.5 1.0

10

20

30

40

50

60

Wave vector k (1/Å )

Fre

quency

(TH

z)

0 0.5 1.0 0 0.5 1.0

cca −3π

r θ z

0

1000

2000

ν/c

(cm

–1)

vz

km/s10=v

Twisting Acoustic

Mode km/s17=ω

=dkdv

Longitudinal Acoustic

Mode

km/s7=v

Transverse Acoustic(Doubly

Degenerated)

0 0.5 1.0

cca −3π0 0.5 1.0

Wave vector k (1/Å )

r z

0

1000

2000

ν/c

(cm

–1)

vz

vx

R. Saito et al., Phys. Rev. B, 57 (1998), 4145.

Phonon Dispersion Relations (10,10)-101nm

Phonon Dispersion Relations (10,10)-101nm

Peapod (Fullerene@Nanotube)Peapod (Fullerene@Nanotube)

B. W. Smith, M. Monthioux and D. E. Luzzi, Nature (1998).

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Snapshots of Peapod to Double-walled Carbon Nanotube

at 3000K