Explain Extrinsic Semiconductor.

Extrinsic Semiconductor: An intrinsic semiconductor is able to conduct some current even at room temperature but as this is not helpful for the preparations of different electronic devices. To make this conductive a small amount of impurity is added. That process is termed as doping. A semiconductor to that an impurity at controlled rate is added to make this conductive is termed as an extrinsic semiconductor. When a pentavalent impurity is added a huge of free electrons will exist and the semiconductor is termed as n-type semiconductor. When a trivalent impurity is added many of holes will exist in the semiconductor and this is termed as p-type semiconductor.