Semiconductors

Semiconductors Points : Semiconductors, Definition The materials, in which the conduction and valence bands are separated by a small energy gap arc called semiconductors. Silicon and germanium are the commonly used semiconductors. A small energy gap means that a small amount of energy is required to free the electrons by moving them from the valence band into the conduction band. The semiconductors behave like insulators at 0 K because flow electrons are available in the conduction band, However, at room temperature, a significant number of electrons are available in the conduction band. If the temperature is further increased (above room temperature) more valence electrons will acquire energy to jump into the conduction band. Thus like insulators, semiconductors also have negative temperature coefficient of resistance. It means that conductivity of semiconductors increases with the increase in temperature.