01-08-2012, 01:00 PM
CARBON NANO TUBES WITH A CASE STUDY OF SWCNT
CNT.pptx (Size: 1.16 MB / Downloads: 48)
INTRODUCTION
Carbon nanotubes are wires of carbon with nanometer diameters and lengths of many microns.
Their name is derived from their size, since the diameter of a nanotube is in the order of a few nanometers (approximately 1/50,000th of the width of a human hair), while they can be up to 18 centimeters in length.
Nanotubes are formed by rolling up a graphene sheet into a seamless cylinder.
Single Walled Carbon Nano-Tubes (SWCNT):
The structure of a SWCNT can be conceptualized by wrapping a one-atom thick layer of graphite called graphene sheet into a seamless cylinder.
They can be approximated as one-dimensional structures.
Most SWCNTs have a diameter of close to 1 nm, with a tube length that can be many thousands of times larger.
PROCESSING TECHNIQUES
Arc discharge
Laser ablation
Chemical vapor deposition
Laser Ablation Method
A laser is used to vaporize a graphite target in an oven at 12000C.
The graphite target gets vaporized to form small carbon molecules and atoms which condense to form single walled nano-tubes held together by Van der Waals forces.