Question

Distinguish between extrinsic and intrinsic semi conductors.

Answer 1

INTRINSIC SEMICONDUCTORS	EXTRINSIC SEMICONDUCTORS
1. Intrinsic semiconductors are crystals of pure elements like silicon and germanium.	1. When some impurity is added in the intrinsic semiconductor, we get extrinsic semiconductor.
2. The number density of electrons is equal to number density of holes i.e. $n_e=n_h$.	2. Number density of electrons is not equal to that of holes. i.e. $n_e\ne n_h$.
3. The electrical conductivity is low.	3. The electrical conductivity is high.
4. Resistivity is higher.	4. Resistivity is low.
5. The electrical conductivity mainly depends on their temperatures.	5. The electrical conductivity depends on the temperature as well as amount of impurity added in them.