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Department of Materials Science and Engineering, Northwestern University
Nanomaterials
Lecture 6: Carbon Nanomaterials
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Department of Materials Science and Engineering, Northwestern University
7 nm
STM Image
AFM Image
Carbon Nanomaterials
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Department of Materials Science and Engineering, Northwestern University
C60 was established by mass spectrographic analysis by Kroto and Smalley in 1985 C60 is called a buckminsterfullerene or buckyball due to resemblance to geodesic
domes designed and built by R. Buckminster Fuller
G. Timp,Nanotechnology, Chapter 7
Fullerenes
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Endohedral doping of fullerenes leads to the formation of a dipole moment thatinfluences solubility and other properties.
G. Timp,Nanotechnology, Chapter 7
Endofullerenes
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5/27Department of Materials Science and Engineering, Northwestern University
G. Timp,Nanotechnology, Chapter 7
Electronic Structure of Molecular and Solid C60
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Calculated local density of states for Si(100)
Structure of C60
1.0
0.8
0.6
0.4
0.2
0.0
dI/dV(
A.U.)
-2 -1 0 1 2Energy (eV)
C60Si Dangling BondH-passivated Si
Spectroscopic variation among surface features
70 x 70
3-D STM Topograph
C60
Dangling
Bonds
Si
Ge
LUMO peak
Single Molecule STM Spectroscopy of C60
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G. Timp,Nanotechnology, Chapter 7
Rolled Up From Graphene Sheets:Carbon Nanotubes
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Carbon Nanotube Synthesis:Carbon Arc Discharge
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Carbon Nanotube Synthesis:Chemical Vapor Deposition
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Carbon Nanotube Synthesis:Laser Ablation
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Department of Materials Science and Engineering, Northwestern University
G. Timp,Nanotechnology, Chapter 7
Chirality of Carbon Nanotubes
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Department of Materials Science and Engineering, Northwestern University
G. Timp,Nanotechnology, Chapter 7
Energy Band Diagrams of Carbon Nanotubes
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Electrical Properties of Graphite
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Electrical Properties of Straight Nanotubes
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Electrical Properties of Twisted Nanotubes
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Department of Materials Science and Engineering, Northwestern University
G. Timp,Nanotechnology, Chapter 7
Bandgap of Semiconducting Nanotubes
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Department of Materials Science and Engineering, Northwestern University
MWNT bandgap is proportional to 1/d At room temperature,
MWNTs behave like metals since d ~ 10 nm
Only the outermost shell carries current in an undamaged MWNT
Electrical Properties of MWNTs
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Other Properties of SWNTs
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Other Properties of SWNTs
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).
Nanotubes as Interconnects
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Department of Materials Science and Engineering, Northwestern University
Although a cross-sectional view of a MWNT shows several
cylindrical shells, only the outermost shell carries current in
an undamaged MWNT.
Current Carrying Capacity of MWNTs
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Department of Materials Science and Engineering, Northwestern University
8
6
4
2
0
Currentdensity(x10
13
A/m
2)
1614121086420
Electric field (x106
V/m)
Maximum current density: 6.8 x 1013
A/m2
Maximum electric field: 1.6 x 10
7
V/m
Maximum current densities of potential interconnect materials: Metals: 1010 1012 A/m2
Superconductors:Jc ~ 1012 A/m2
MWNTs: >51013
A/m2
Representative MWNT I-V Curve:
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Department of Materials Science and Engineering, Northwestern University
Experimental method: Monitor the current as a function of time
while stressing the MWNT at a fixed voltage.
Before Electrical Stress
1 m2 AFM image
After Failure
1 m2 AFM image
Electrically Stressed MWNTs
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins, et al., Phys. Rev. Lett., 86, 3128 (2001).
Multiwalled Carbon Nanotube Failure
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Department of Materials Science and Engineering, Northwestern University
G. Timp,Nanotechnology, Chapter 7
Device Applications of Nanotube Junctions
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins, et al., Science, 292, 706 (2001).
Engineering Carbon NanotubesUsing Electrical Breakdown
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Department of Materials Science and Engineering, Northwestern University
P. G. Collins, et al., Science, 292, 706 (2001).
Engineering Carbon NanotubesUsing Electrical Breakdown