Indicate differences between intrinsic and extrinsic semicon

Indicate differences between intrinsic and extrinsic semiconductor.

Solution

Intrinsic Semiconductor Extrinsic semiconductor Intrinsic semiconductors, also called an undoped semiconductors or i-type semiconductor, are pure semiconductor without any significant dopant species present. The number of charge carriers is therefore determined by the properties of the material itself instead of the amount of impurities. These are impure semiconductors . When a small quantity of impurity is mixed in a pure or intrinsic conductor , conductivity of semiconductor increases . Such an impure semiconductor is called extrinsic semiconductor. Conductivity of intrinsic semiconductors is poor Conductivity of extrinsic semiconductors is large. Number of electrons in conduction band and holes in valence band are approximately equal . If it is an n-type electrons are in majority and if it is a p-type holes are in majority Fermi energy level lies at the centre of forbidden energy gap. In n-type Fermi-level lies near the bottom of conductioin band and in p-type near the top of valence base The electrical conductivity of intrinsic semiconductors depends on their temperatures The electrical conductivity depends on the temperature and the amount of impurity added in them Electrical conductivity is low Electrical conductivity is high