Experimental and Molecular Dynamics Studies Related with Carbon Nanotubes Shigeo Maruyama Dept. of Mech. Eng., The University of Tokyo http://www.photon.t.u-tokyo.ac.jp/~maruyama/ E-mail: [email protected]Colloquium Micro/Nano Thermal Engineering @ Seoul, 2002/2/18 (a) C 60 (c) La@C 82 (b) C 70 (e) SWNT (f) MWNT C 60 PVWin (d) Sc 2 @C 84 Typical Structures of Fullerene & Nanotubes What is Carbon Nanotube? Chirality and Radius of SWNT (10,10) Armchair (10,0) Zigzag (10,5) Chiral a 1 a 2 http://vortex.tn.tudelft.nl/~dekker/nanotubes.html STM Image of Individual Atoms TEM Pictures of SWNT Ropes Individual tube diameter: 1.3 nm Spacing: 0.34 nm Misalignments and Terminations TEM from Smalley et al. at Rice University About 100 SWNTs
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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/
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
7
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