semiconductor diodes and transistor

Question 1

what is semiconductor material

Answer 1

The basis of any solid state device is called semiconductor material. The semiconductor material has a resistivity higher than that of conductor and lower than that of insulator

Question 2

Special properties of semiconductors

Answer 2

1. They have negative temperature coefficient of resistance. (I. e) electrical resistance of semiconductor decreases with increase in temperature
2. The electrical conductivity of a semiconductor can be manipulated by the addition metallic impurities.
3. Metals conduct by means of mobile negative charges namely electrons alone whereas semiconductors conduct electric current by two distinct and independent modes of motion of electrons. In one mode, electrons flow as free electrons and in the other mode, electron flow can be described only in terms of positive charges known as ‘holes’

Question 3

examples

Answer 3

Germanium and Silicon are the two widely used semiconductors. Other semiconductors are GaAS, PbSc etc.