Transcript Carbon Nanotubes - The University of Oklahoma Department

Carbon Nanotubes
Zach Blankenship, Jeff Harwell, Tony Mondejar
Today's Presentation

Introduction
 What is a Nanotube
 History of Nanotube Research
 Nanotube Structure and Properties
 Applications of Nanotubes
 Conclusion
Introduction
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Why are we interested in Nanotube
development?
What is a Nanotube?
History of the Nanotube?
How was it discovered…(who, where and
when)?
What are different kinds of Nanotubes?
What are some properties of a Nanotube?
What is Nanotechnology?
Applications of Nanotechnology?
Chronological Milestones

1985 Researchers discover soccer ball shaped
molecule created by linking together 60 or
more carbon atoms. It was later named after
R. Buckmister Fuller (buckyballs).
 1991 Observation and identification of
nanotubes in fullerene soot by Sumio Iijima.
 1992 Predictions of metallic/insulating
properties.
 1993 Synthesis of single-walled nanotubes.
Chronological Milestones
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1996 Measurement of individual
multiwalled tubes.
 1996 Individual nanotube used as an
AFM tip.
 1996 Production of bulk, monodisperse
1.4 nm SWNTs.
 1997 Observation of single-electron
effects in individual SWNTs and bundles.
Single Walled Nanotube
Buckyballs inside a SWNT
Properties of Fullerene
Nanotubes
 Pure
form of Carbon
 Structure
 Conductivity
 Tensile Strength
 Elasticity
Carbon Nanotubes
Forms of Carbon
mmptdpublic.jsc.nasa.gov/jscnano/
(Photo courtesy of Dan Colbert, Rice University)
Schematic of Nanotube
Structure
d2=((n2 + m2 + nm)1/2)0.0783
http://www.pa.msu.edu/~adamsth3/nanotube/properties.html
Fundamental Gap
MWNT Conductance vs. Depth
(Go being the conductance quantum 1/13 kohm).
http://www.gtri.gatech.edu/res-news/BALANCE.html
Tensile Strength of Engineering
Materials
Gpa, log scale
Amazingly Flexible Tubes
Carbon Nanotubes and Related
Structures, Harris, p197
The "…force
unravels the
tube as a
knitter would
unravel the
sleeve of a
sweater."
(Yakobson &
Smalley, 1997)
(Yakobson & Smalley, 1997)
The table below gives a comparison of the
magnitude of elastic modulus between
substances.
Material
Modulus (GPa)
Diamond
1000
Silicon
107
Iron
196
Low Alloy Steels
200-207
Nylon
3-3.4
Silicon Carbide (SiC)
450
Carbon Nanotubes
approx. 630 (Cornell, 1996)
The top picture
shows a bent
nanotube. The
bottom picture
shows the same
nanotube after
release from the
matrix.
From: Ebbesen (ed.), Carbon Nanotubes: Preparation and Properties,
CRC Press, Boca Raton (1997).
Current State of the Research
 A Few Working Applications
– Polymer Reinforcement
– Electron Guns
– Scanning Probe Microscope Tips
 A Lot
of Hype and Theoretical Work
– Electronic Circuit Elements
– Artificial Nanostructures
Polymer Reinforcement
Carbon Nanotubes and Related Structures, Harris, p206
Electron Guns

Nanoscale pointed conductors used as
electron field emitters
 Sharp Nanotube Points Make Them Ideal as
Electron Guns
 One application of Electron Guns is in Field
Emission Displays
– Electrons Emitted from Source Exciting a
Phosphor
Nanotube in a Field Emission
Display
Carbon Nanotubes and Related Structures, Harris, p150
Scanning Probe Microscope
Tips

Large, Blunt Conventional Tip Limit
Microscope Resolution
 Sharp Point of Nanotube Provides for High
Resolution Imaging
– Used as Tips for Atomic Force Microscopy
– Electrical Conductivity Allows for Use In
Scanning Tunneling Microscopy
A New Kind of Pencil
Carbon Nanotubes and Related Structures, Harris, p 209
Nanotubes as Circuit
Elements
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Nanotubes Conductivity is Determined by
Chirality and Environment
– Semiconducting
– Conducting
– Insulating
Testing A Nanotube For
Electrical Properties
Carbon Nanotubes and Related Structures, Harris, p 128
Nanotube Field Effect
Transistor
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Semiconducting SWNT Placed Between
Two Electrodes
 Appling Voltage To Gate Electrode Changes
SWNT from Conducting the Insulating
Carbon Nanotubes and Related Structures, Harris, p133
Nanostructures
Looks
Cool. Can
We Build
It?
Carbon Nanotubes and Related Structures, Harris, p 268
In Conclusion

Nanoscale Tubes Made From Carbon
Hexagons
 Exceptional Physical Properties
– Semiconducting, Conducting or Insulating
– High Strength

Field of Research is Only 9 Years Old
 Best and Most Innovative is Yet to Come