Semiconductor

Semiconductor, solid with an electrical conductivity that lies between the high conductivity of metals and the low conductivity of insulators. A semiconductor device is an electronic element fabricated from crystalline materials, such as silicon or germanium, that in the pure state, are neither good conductors nor good insulators and are unusable for electronic purposes. When certain impurity atoms, such as phosphorus or arsenic, are diffused into the crystal structure of the pure metal, the electrical neutrality is upset, introducing positive or negative charge carriers.