Extrinsic Semiconductors

The highest energy level that an electron can occupy at the absolute zero temperature is known as the Fermi Level. The Fermi level lies between the valence band and conduction band because at absolute zero temperature, the electrons are all in the lowest energy state.The Fermi-level in an intrinsic semiconductor is nearly midway between the conduction and valence band.In doped semiconductors, p-type and n-type, the Fermi level is shifted by the impurities to towards valence band and the conduction band respectively.