Module I
Band theory of solids - Conductors, semiconductors and insulators - energy band diagram. -Semi conductor materials and their properties: elemental semiconductors- the energy band model of semiconductors. Valance band model of semiconductor equilibrium concentration of electrons and holes- the fermi level and energy distribution of carriers inside the bands- temperature dependence of carrier concentration inside the bands - Carrier transport in semi conductors - drift of carriers in electric fields, carrier flow by diffusion - constancy of fermi level across junction, Excess carriers in semi conductors - injection of excess carriers - recombination of excess carriers - continuity equation - current flow equation..
Module II
PN junction- Abrupt PN junction - energy band diagram - barrier potential, biasing PN junction, excess carrier calculation - current components diffusion - drift - boundary conditions for long and short diodes - PN junction characteristics - calculation of diffusion – depletion layer capacitance - simple model - transient ac condition - principle of zener and avalanche diodes - Photodiodes, Tunnel diode, PIN diode & Varactor diode.
Module III
Bipolar junction transistors - NPN, PNP types, Basic structures - biasing - mechanism of carrier flow - current components in transistors boundary conditions in active region - solution for short base width - base width modulation - Transistor configurations - Characteristics - current amplification factors - relations between alpha & beta - comparison Ebbers - Moll model - - basic principles of phototransistors - UJT, characteristics.
Semiconductor heterojunctions - V-I characteristics - real heterojunctions - frequency limitation of transistor - transit time effect.
Module IV
Field effect transistors: JFET - basic structures - principle of operation - Characteristics and current equation, MOSFET - semiconductor surfaces - C - V characteristics - the Si - SiO2 System - basic structures and operating principles - current equation - V-I characteristics - simple model – CMOS- structure, operation.
