8/8/2019 Carbon Nano Materials 1

1/27

Department of Materials Science and Engineering, Northwestern University

Nanomaterials

Lecture 6: Carbon Nanomaterials

8/8/2019 Carbon Nano Materials 1

2/27

Department of Materials Science and Engineering, Northwestern University

7 nm

STM Image

AFM Image

Carbon Nanomaterials

8/8/2019 Carbon Nano Materials 1

3/27

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

8/8/2019 Carbon Nano Materials 1

4/27Department of Materials Science and Engineering, Northwestern University

Endohedral doping of fullerenes leads to the formation of a dipole moment thatinfluences solubility and other properties.

G. Timp,Nanotechnology, Chapter 7

Endofullerenes

8/8/2019 Carbon Nano Materials 1

5/27Department of Materials Science and Engineering, Northwestern University

G. Timp,Nanotechnology, Chapter 7

Electronic Structure of Molecular and Solid C60

8/8/2019 Carbon Nano Materials 1

6/27Department of Materials Science and Engineering, Northwestern University

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

8/8/2019 Carbon Nano Materials 1

7/27Department of Materials Science and Engineering, Northwestern University

G. Timp,Nanotechnology, Chapter 7

Rolled Up From Graphene Sheets:Carbon Nanotubes

8/8/2019 Carbon Nano Materials 1

8/27

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

8/8/2019 Carbon Nano Materials 1

9/27

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

8/8/2019 Carbon Nano Materials 1

10/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Carbon Nanotube Synthesis:Laser Ablation

8/8/2019 Carbon Nano Materials 1

11/27

Department of Materials Science and Engineering, Northwestern University

G. Timp,Nanotechnology, Chapter 7

Chirality of Carbon Nanotubes

8/8/2019 Carbon Nano Materials 1

12/27

Department of Materials Science and Engineering, Northwestern University

G. Timp,Nanotechnology, Chapter 7

Energy Band Diagrams of Carbon Nanotubes

8/8/2019 Carbon Nano Materials 1

13/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Electrical Properties of Graphite

8/8/2019 Carbon Nano Materials 1

14/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Electrical Properties of Straight Nanotubes

8/8/2019 Carbon Nano Materials 1

15/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Electrical Properties of Twisted Nanotubes

8/8/2019 Carbon Nano Materials 1

16/27

Department of Materials Science and Engineering, Northwestern University

G. Timp,Nanotechnology, Chapter 7

Bandgap of Semiconducting Nanotubes

8/8/2019 Carbon Nano Materials 1

17/27

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

8/8/2019 Carbon Nano Materials 1

18/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Other Properties of SWNTs

8/8/2019 Carbon Nano Materials 1

19/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Other Properties of SWNTs

8/8/2019 Carbon Nano Materials 1

20/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Nanotubes as Interconnects

8/8/2019 Carbon Nano Materials 1

21/27

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

8/8/2019 Carbon Nano Materials 1

22/27

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:

8/8/2019 Carbon Nano Materials 1

23/27

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

8/8/2019 Carbon Nano Materials 1

24/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins, et al., Phys. Rev. Lett., 86, 3128 (2001).

Multiwalled Carbon Nanotube Failure

8/8/2019 Carbon Nano Materials 1

25/27

Department of Materials Science and Engineering, Northwestern University

G. Timp,Nanotechnology, Chapter 7

Device Applications of Nanotube Junctions

8/8/2019 Carbon Nano Materials 1

26/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins, et al., Science, 292, 706 (2001).

Engineering Carbon NanotubesUsing Electrical Breakdown

8/8/2019 Carbon Nano Materials 1

27/27

Department of Materials Science and Engineering, Northwestern University

P. G. Collins, et al., Science, 292, 706 (2001).

Engineering Carbon NanotubesUsing Electrical Breakdown