CBSE Class 12-science Answered

Depending on the type of impurity added, the extrinsic conductors can be divided into two classes namely

(i) n-type semiconductors and

(ii) p-type semiconductors.

(i)  n-Type Extrinsic Semiconductors: When a small amount of pentavalent impurity, such as arsenic, antimony, bismuth or phosphorous, is added to a pure semiconductor crystal during the crystal growth, the resulting crystal is called as n-type extrinsic semiconductor.

p-type Extrinsic Semiconductors.. When a small amount of trivalent impurity such as boron, gallium, indium or aluminum, is added to a pure semiconductor crystal growth, the resulting crystal is called the p-type extrinsic semiconductor.