1. Chemical Vapor Deposition A Simple method of bottom up Fabrication

2. Top Down Fabrication Top down fabrication is the process of reducing size of the material How to reduce nano –size? Electron lithography e Only required material is protected by a mask and the exposed material is etched away

3. Nano-Electronics “Nano” is from Greek word nanus meaning dwarf Semiconductor or micro-electronic devices that have been shrunk to the nanoscale.[ billionth (10 -9 ) of a meter]. Size  10 -100nm Supports information technology, defense, biosciences, and energy From Gorden Moore Law: exponential increase of transistor count on integrated circuit (IC) chips and an exponential decrease of their sizes with time These are switch

4. Semiconductor Electron and Holes in semiconductor Insulator Semiconductor

5. CVD Gas inlet Gas outlet Source Material Substrate Factors : 1.Temperature control 2.Gas type 3.Flow rate 4.Substrate distance 5.Type of substrate 6.Catalyst Applications: integrated circuits, optoelectronic devices and sensors, Nanowires Nanoparticles fine metal and ceramic powders protective coatings

6. Thermodynamics Chemical Reactions The Gibbs free-energy function G: G = H – TS, and  G =  H - T  S IInd Law of Thermodynamics: spontaneous reactions occur at P, T = const, if  G < 0

7. Electrospinning Electrospinning is a technique of producing polymer micro- and nanofiber non-woven mats of varying thicknesses. High Voltage Solutions Micro Pore Fiber Collectin poly(vinyl alcohol), Polyvinylpyrrolidone, Polyvinyl Acetate Organic materials easily soluble is water Solution of A + Solution of B + PVA (or PVP) Physics : Action of Point

8. Heat Treatment First stabilize the fibre Remove the fibre Select right temperature for the chemical reaction Results depends on: 1.Electrospining Condition a) Humidity b) Room temperature c) Solubility d) Electric Field 2.Heating 3.Type of gas used and Flow rate Use: Nanoelectronics, Medical ( Contact lens), Glamour's cloths, Manquinn Thermal insulatin fibre.