A material, usually crystalline, with electrical conductivity that is intermediate between that of metals and that of insulators. The conductivity varies depending on the amount and chemical nature of impurity elements incorporated during the manufacturing process. The ability to control this variation is the basis for the operation of all semiconductor devices such as transistors, light emitting diodes, and injection lasers.
A material whose ability to carry on an electric current falls between those of metals and nonmetals.
Semiconductor is a material in which the highest occupied energy band (valence band) is completely filled with electrons at = 0 K, and the energy gap to the next highest band (conduction band) ranges from 0 to 4 or 5 eV. With increasing temperature electrons are excited into the conduction band, leading to an increase in the electrical conductivity.