This document discusses carbon nanotubes. It describes carbon nanotubes as having a diameter as small as 1nm and being made of rolled graphene sheets. Carbon nanotubes can be single-walled, multi-walled, or double-walled. They have extraordinary properties including high tensile strength, electrical and thermal conductivity. Potential applications include conductive plastics, structural materials, electronics, and biosensors. Common fabrication methods are electric arc discharge, laser ablation, and chemical vapor deposition.

1. CARBON NANOTUBES
WANAMBWA ZACK NICHOLAS

2. CARBON NANOTUBES
• CNT is a tubular form of carbon with diameter
as small as 1nm. Length: few nm to microns.
• CNT is configurationally equivalent to a two
dimensional graphene sheet rolled into a
tube.

3. CARBON NANOTUBES
• A CNT is characterized by its Chiral Vector: Ch
= n â1 + m â2,
Chiral Angle with respect to the zigzag axis.

4. CARBON NANOTUBES
• Their electrical
characteristics
differ depending
on these
variations, and
variations in
diameter acting
either as metals
or as
semiconductors.

5. CARBON NANOTUBES
CARTEGORIES:
• Carbon Nanotubes can be categorized by their
structures:
1. Single-wall Nanotubes (SWNT)
2. Multi-wall Nanotubes (MWNT)
3. Double-wall Nanotubes (DWNT)

6. CARBON NANOTUBES

7. CARBON NANOTUBES
PROPERTIES:
• Carbon nanotube is one of the strongest
materials in nature.
• Overall, Carbon Nanotubes show a unique
combination of stiffness, strength, and
tenacity.
• Thermal and electrical conductivity are also
very high, and comparable to other
conductive materials.

8. CARBON NANOTUBES
PROPERTIES:
• CNTs have Very High Tensile Strength
Sheet of graphite form a planar honeycomb
lattice, each atom is connected via a strong
chemical bond to three neighboring atoms.
Because of these strong bonds, the basal-plane
elastic modulus of graphite is one of the largest
of any known material.

9. CARBON NANOTUBES
PROPERTIES:
CNTs have High Electrical Conductivity:
• Their conductivity has been shown to
be a function of their chirality , as
well as their diameter.
• CNTs can be either metallic or semiconducting in their electrical
behavior.
• (a) Armchair NT exhibits metalic
behavior at Fermi energy, while (b)
zigzag NT is a small gap semicinductor

10. CARBON NANOTUBES
PROPERTIES:
CNTs have High Thermal Conductivity
• New research from the University of Pennsylvania
indicates that CNTs may be the best heatconducting material man has ever known.
• Ultra-small SWNTs have even been shown to
exhibit superconductivity below 20oK,
• May someday also find applications as miniature
heat conduits in a host of devices and materials

11. CARBON NANOTUBES
APPLICATIONS:• Conductive plastics
• Structural composite
materials
• Flat-panel displays
• Gas storage
• Antifouling paint
• Micro- and nanoelectronics
• Radar-absorbing coating
• Technical textiles
• Ultra-capacitors
• Atomic Force Microscope
(AFM) tips
• Batteries with improved
lifetime
• Biosensors for harmful gases
• Extra strong fibers

12. CARBON NANOTUBES
Advantages:
Disadvantages
• Extremely small and
lightweight, making them
excellent replacements for
metallic wires
• Resources required to produce
them are plentiful, and many
can be made with only a small
amount of material
• Are resistant to temperature
changes, meaning they
function almost just as well in
extreme cold as they do in
extreme heat
•
•
•
•
•
Despite all the research, scientists
still don't understand exactly how
they work
Extremely small, so are difficult to
work with.
Currently, the process is relatively
expensive to produce the
nanotubes
Would be expensive to implement
this new technology in and replace
the older technology in all the
places that we could
At the rate our technology has
been becoming obsolete, it may be
a gamble to bet on this technology

13. CARBON NANOTUBES
FABRICATION OF CARBON NANOTUBES:
1. Elecritic Arc Discharge: Most common method of CNT fabrication
1. A current is run through an anode, or
a positively charged piece of carbon.
2. This current jumps through a plasma
material to a cathode, or a negatively
charged piece of carbon, where there
is an evaporation and deposition of
carbon particles in through the
plasma.
3. Finally an outer hard-shell region
made of decomposed graphite is
formed and an inner core region with
loosely packed columns which consist
of straight, stiff multishell carbon
nanotubes and closed polyhedral
particles

14. CARBON NANOTUBES
FABRICATION OF CARBON NANOTUBES:
2. Laser Ablation:
• Uses an intense laser pulse to vaporize a
carbon target, which also contains small
amount of metals such as nickel and
cobalt and is placed in a tube furnace at
1200oC.
• Inert gas is passed through the chamber
carrying the grown nanotubes on a cold
finger for collection.
• This method mainly produces SWCNT in
the form of ropes

15. CARBON NANOTUBES
FABRICATION OF CARBON NANOTUBES:
•
•
•
•
3. Chemical vapor deposition
A mixture of hydrocarbon, metal catalyst
along with inert gas is introduced into the
reaction chamber.
During the reaction, nanotubes form on the
substrate by the decomposition of
hydrocarbon at temperatures 700–900oC
and atmospheric pressure.
The diameters of nanotubes that are to be
grown are related to the size of the metal
particles
This technique offers more control over the
length and structure of the produced
nanotubes compared to arc and laser
methods.