Semiconductors are materials which have electrical conductivity between that of an good conductors (metals) and nonconductors or insulator(ceramics); a type of material having a lower energy valence band that is nearly completely filled with electrons and a higher energy conduction band that is nearly completely empty of electrons, with energy gap between the two bands; pure materials usually exhibit electrical conductivity that increases with temperature because of an increase in the number of charge carriers being promoted to the conduction band. Examples are Silicon, Germanium, Gallium Arsenide and Cadmium Selenide.
This course is called Semiconductors, concerned with the physical characteristics of semiconductor materials. The course is designed for second semester for second year students of the Department of General Science, College of Basic Education at Salahaddin University-Erbil.