carbon nanotubes - seminar iete

CARBON NANOTUBES: Properties, Synthesis &

Applications in Electronic Devices

Chemical Element Physical forms Covalently bonded n/w Allotropes Physical Properties : Transparent/Opaque Hard/Soft Thermal Conductivity Electrical Conductivity

NANOTUBE:

Nanometer scale Tube-like Structure.

Well structured network of Hexagon atoms that connect together in a rolled fashion that creates a cylinder without a seam.

Width- 1nm

Length – Depending on requirements (can be few nm, thousands of microns, or ten thousands of microns).

CARBON NANOTUBES (CNTs):

Wires of pure carbon with nm(10-9) diameters and lengths of many microns.

Types : SWCNT & MWCNT

SWCNT : Single atomic layer thick sheet of graphite rolled into a seamless cylinder.

MWCNT : Several concentric Nanotube Shells.

Prof. Sumio Iijima, IBM. Japan

HISTORY

Initial History of Nanotubes started in 1970 with preparation of carbon filaments but it failed to meet the requirements for width and thus were deemed.

In 1991, the true first invention of nanotube was finally made.

CNT was discovered by Professor Sumio Iijima of IBM in Japan.

STRUCTURE OF CNTs

Depends on rolling up the graphene sheet.

3 Geometries: Armchair Zigzag Chiral.

Also referred as Flavors.

PROPERTIES OF CNTs

ELECTRONIC PROPERTIES OF CNTs:Understanding electronic properties of a graphene sheet.

Most Directions: there is a bandgap electrons are not free Graphene: zero-gap semiconductor.

Special Directions: electrons flow easily Graphene: metallic

Bulk Graphite: conducting metallic path which connects any two points. Graphite: conducts electricity.

Rolled upSpecial direction: along the axis of NT.Directions: Metallic SemiconductingMolecular Electronic Technologies.

SYNTHESIS METHODS FOR CARBON NANOTUBES

1) ARC DISCHARGE CHAMBER 2) LASER ABLATION METHOD

3) CHEMICAL VAPOR DEPOSITION (CVD) 4) HYDROCARBON FLAMES METHOD

CNT APPLICATIONS IN ELECTRONIC DEVICES1) Transparent Conductive Films:

UNDER ELECTRON MICROSCOPE TOUCH SCREENS

PLASTIC SOLAR CELL

OLED LIGHTING FLAT PANEL DISPLAY SCREEN

2) Printable Transistors:

WAFER OF CNT TRANSISTORS

3) Field Emission:

4) Integrated Circuits:

5) CNT Fibers: 6) CNT Paper Battery

Carbon Nanotubes are the next step in Miniaturizing Electronic Circuits, Replacing Silicon Transistors and Diodes, which are fast reaching the Theoretical limits of Size and Speed of Operation.

THANK YOU -GARGI KAPADIA