Low Dimensional System & Nanostructures
Angel Rubio & Nerea Zabala
Carbon Nanotubes
A New Era
By
Afaf El-Sayed
2009
Outline
World of Carbon
- Graphite
- Diamond
- Fullerene
Carbon Nanotubes CNTs
- Discovery of CNTs
- Basic Structure & Types of Nanotubes
- Electronic Structure of CNTs
Properties & Applications of CNTs
sp
World of Carbon
sp2
3
sp
Graphite
In graphite, The sp2 orbital
form the strong σ-bonds
between carbon atoms in
the graphite planes, while
the pz, or π, orbital provide
the weak Van der waals
bonds between the
planes.
&
Diamond
In diamond, each
carbon atom has four
nearest neighbors.
The sp3 orbital form
the strong σ-bonds
between carbon
atoms.
Fullerene
In the C60 molecule, the carbon atoms are
bonded in a structure made up of 20
hexagons and 12 pentagons. Each of the
carbon atoms in C60 is joined to three
neighbors, so the bonding is the bonding is
essentially sp2, although there may be a
small a mount of sp3 character due to the
curvature.
The carbon 60 atoms are bonded
together in an array of hexagons and
pentagons, like a soccer ball. These
molecules are called Buckminster
fullerenes in honor of Buckminster Fuller
who first designed similarly shaped
geodesic domes.
Carbon Nanotubes
Discovery of CNTs
Since the early 1960s, Harry Kroto, of the University of Sussex, had been
fascinated in the processes occurring on the surfaces of stars, and
believed that experiments on the vaporization of graphite might provide key
insights into these processes.
On the other hand, Richard Smalley, of Rice University, Houston, had
different reasons for being interested in what might happen when one
vaporizes carbon.
In August 1985, the two scientists began the now famous series of
experiments on the vaporization of graphite. They were immediately struck
by the formation of C60. The discovery of C60, published in nature in
November 1985, had an impact which extended way beyond the confines
of academic chemical physics, and marked the beginning of a new era in
carbon science.
Perhaps, Carbon nanotubes are the most important fruits of this research.
Discovered by the electron microscopist Sumio Iijima, of the NEC
laboratories in Japan, in 1991, these ‘molecular carbon fibers’ consist of
tiny cylinders of graphite, closed at each end with caps which contain
precisely six pentagonal rings.
ϕ
Basic Structure & Types of CNTs
ϕ
R = na1 + ma 2
0 ≤ |m| ≤ n & Φ<30o
SWNTs, MWNTs and!!!!!
Neural Tree
Electronic Structure of Graphene
“Zero-bandgap Semiconductor”
Unit cell
π* anti-bonding
orbitals
π bonding
orbitals
Brillouin Zone
Graphene to SWNT
C h = na1 + ma2
T = t1a1 + t 2 a2
(
r
r
1
− t 2 b1 + t1b2
N
r
r
1
K2 =
m b1 − n b2
N
K1 =
(
)
)
Different Properties of CNTs
Properties
Nanotubes
Estimated at 1 X 109A/cm2
Current carrying capacity for MWCNT: 20 – 50 nm
By Comparison
Copper wires burn out at
about 1X 106 A/cm2
Field Emission
Can activate phosphors at Molybdenum tips require
1– 3 volts if electrodes are fields of 50 – 100 V/m and
spaced 1 micron apart
have very limited lifetimes
Heat Transmission
Predicted to be as high as
6,000 W/m.K at room
temperature
Nearly pure diamond
transmits heat at 3,320
W/m.K
Temperature Stability
Stable up to 2,800 oC in
vacuum, 750 oC in air
Metal wires in microchips
melt at 600 – 1,000 oC
Elasticity
Elastic modulus ~ 103 GPa ~ 200 GPa for steel
Yield Strength ~ 65 GPa
~ 0.8 GPa for steel
Applications of CNTs
Glucose sensors
CNT-FETs
CNT scanning tip
CNT-Solar Cells
CNT- Flexible Displays
CNT interconnects
Neural Tree
Future!!!!!!
Space Elevator
Space Platform
Faster, Better and Cheaper Space Aircrafts
Conclusion
A new era has begun of
Carbon Nano-Science!!!
We should think of our
needs?!!!
Bibliographic Search
R. Saito, et.al, “Physical Propertiest of Carbon Nanotubes”, Imperial College Press, 1998.
Peter Morgan, “Carbon Fibers and their composites”, CRC press, 2005.
Michael J.O’Connell, “Carbon Nanotubes: Properties and Applications”, CRC press, 2006.
Charles Kittle, “Introduction to Solid State Physics”, John Wiley & Sons, Inc., 8th Edition, 2005.
Karl M. Kadish and Rodney S.Ruoff, “Fullerenes: Chemistry, Physics and Technology”, Wiley- IEEE, 2000.
Peter J.F. Harris, "Carbon Nanotubes and Related Structure: New Materials for the Twenty First Century", Cambridge
University Press, 1999.
The nanotube Sites:
http://nanotube.msu.edu/
http://www.pa.msu.edu/cmp/csc/nanotube.html
http://cobweb.ecn.purdue.edu/~mdasilva/Structure.shtml
A. Appenzeller, E. Joselevich, W. Honlein, “Carbon Nanotubes for Data Processing,” in R. Waser, “Nanoelectronics
and Information Technology,” Wiley- VCH (2003).
A. Adams, "Physical Properties of Carbon Nanotubes", as a part of the honours chemistry research project, 2000.
http://www.pa.msu.edu/cmp/csc/ntproperties/electricaltransport.html
Thomas A. Adams, "Physical Properties of Carbon Nanotubes", as a part of the honours chemistry research project,
2000.
http://www.pa.msu.edu/cmp/csc/ntproperties/opticalproperties.html
J. Hone, " Carbon Nanotubes: Thermal Properties", Dekker Encyclopedia of Nanoscience and Nanotechnology, 2004.
D. Yokoyama et al., Appl. Phys. Lett., 91, 263101, 2007.
Christina Guice, Henry C. Foley, Head and Robb Chair and Bo Yi, "Dynamics of Nanotube Synthesis", McNair
Scholar, Pennsylvania State University, 2003.
http://www.nanowerk.com/nanotechnology/introduction/introduction_to_nanotechnology_23.html
NASA web site;
http://www.nasa.gov/vision/space/gettingtospace/16sep_rightstuff_prt.htm
NASA web site;
http://science.nasa.gov/headlines/y2000/ast07sep_1.htm
SPACE.com -- Russians Plan New Space Platform.
http://www.space.com/businesstechnology/080115-technov-russia-platform.html
http://en.wikipedia.org/wiki/Potential_applications_of_carbon_nanotubes