Conduction mechanisms of solids

ABSTRACT Master of Science Thesis CONDUCTION MECHANISMS IN SOLIDS Olcay ÜZENGİ AKTÜRK Anadolu University Graduate School of Natural and Applied Sciences Physics Program Supervisor: Yard.Doç.Dr. Sabiha AKSAY 2002, 69 pages In this thesis, conduction mechanisms in solids have been investigated by means of mctul-scınieoııdııctor contacts. There are four basic transport processes: thermionic emision theory, diffusion theory, generalized thermionic emission- diffusion theory that is synthesis of preceding two theories and tunneling current. The thermionic emission theory is based on the assumption that electron collisions within the depletion region are neglected and carriers have high mobilities. The diffusion theory is applicable to low mobility semiconductors. For a heavily doped semiconductor or for operation at low tempratures the tunelling processes may become the dominant transport processes. In additon, Schottky emission, Frenkel- I'oole emission, ionic conduction and space charge limited have also been considered in thin films. Frenkcl-I'oole emission is thermal excitation of trapped electrons into the conduction band. Ionic conduction is similar to diffussion process. For a given insulator, each conduction processes may dominate in certain temperature and voltage ranges. Keywords: Contacts, Mobility, Thin films, Conductivity, Depletion region II