Electrical behaviour of semiconductors

Définition

A semiconductor is a material that has the electrical characteristics of an insulator, but for which the probability that an electron can contribute to an electric current, although low, is sufficiently high. In other words, the electrical conductivity of a semiconductor is intermediate between that of metals and insulators.

Fondamental

According to energy band theory, a semiconductor material has a band gap small enough to allow electrons from the valence band to easily join the conduction band. If an electric potential is applied to its terminals, a weak electric current is produced, caused both by the displacement of such electrons and by that of the "holes" they leave in the valence band.