Intrinsic Semiconductor: 


Intrinsic means pure, so intrinsic semiconductors are the semiconductors in their purest possible form. The presence of impurity(i.e atom of other material) is low as  1 part 100million parts of semiconductors. The intrinsic semiconductors are insulators  or very very poor conductors, at room temperature.

Example of Intrinsic Semiconductor are Silicon and Germanium.

The increase in temperature or application of increased voltage does not increase their conductivity significantly. Therefore,the intrinsic semiconductors are not practically used for manufacturing of devices.

Intrinsic Semiconductor
Intrinsic Semiconductor

Here created electron-hole pair attracted according coloumbs law, electrons are attracted towards positive(+ve) and holes are attracted towards negative(-ve) terminal of battery and current conduction is takes place.

Extrinsic Semiconductor


Extrinsic means pure, so we can obtain the extrinsic semiconductor from intrinsic ones by adding impurities to them.Impurity is nothing but some other material. The process of adding impurities is called as "Doping". Due to doping the conductivity of the conductors increase. Thus extrinsic semiconductor have better conductivity than the intrinsic semiconductors. Therefore they are used in manufacturing of all the electronic components such diodes, transistors etc. It is of two types.

(i) N-type Semiconductor: When a small amount of pentavalent impurity is added to pure semiconductor, it is called  n-type semiconductor .Arsenic(z=33) and antimony(z=51) is pentavalent element there impurities are also called donor impurities.


n-type semiconductor
(a) n-type semiconductor


Here These free electrons is responsible to conduct current in n-type semiconductors. The process of adding impurities to a semiconductor is called doping for 10^8 atoms of atom one impurities atom is added.


(ii) p-type semiconductor: when a small amount of trivalent impurities are added to a pure semiconductor, It is called p-type semiconductor.
Gallium(z=31) and Indium(z=49) is the example impurity these impurities are also called acceptor impurities.
p-type semiconductor
(b) p-type semiconductor


Here holes are responsible to conduct current in p-type semiconductor holes have +ve charge when voltage is applied across p-type material the holes are attracted towards -ve terminal of battery and current conduction takes place.