Portale di Ateneo - En.Unibs.it

Elements quantum mechanics. Semiconductor materials: crystal lattices, atomic bond, defects, energy bands. Electrical conduction in solids: drift current, effective mass, concept of energy gap, metals, insulators and semiconductors. Density of states, Fermi-Dirac statistics. Charge distribution in semiconductors: equilibrium distribution of electrons and holes, intrinsic concentrations and intrinsic Fermi level. Doping: atoms and energy levels, extrinsic semiconductors, degenerate electronic states, donors and acceptors, complete ionization and freezing of impurities, the Fermi level and its variation with concentration and temperature. Transport phenomena: drift current, conductivity and mobility, saturation velocity at high fields, diffusion current. Spatial distribution of impurities: gradients and induced electric fields, Einstein relations. Semiconductor out of equilibrium: continuity equations, excess carriers, generation and recombination function, optical generation, Auger generation, avalanche generation, Zener effect. Transport equations and applications. Small injections. Experiment of Haynes-Schockley. Quasi-Fermi levels.

Electronic Devices.
Pn junction in equilibrium, diode. Impact ionization, breakdown and Zener diodes. JFETs. Ohmic contacts and Schottky contacts, Schottky diodes. Bipolar transistor. MOS capacitor. MOS transistor. Photodiode and phototransistor solar cells.