By adding impurities in semiconductor, the bulk resistance of a semiconductor_______
Right Answer is:
By adding impurities in semiconductors, the bulk resistance of a semiconductor decreases.
Impurity Level in n-type Semiconduction: In an n-type semiconductor the impurity level appears close to the conduction band and therefore, at ordinary temperature electrons can easily move from the impurity level to the conduction band and this thing contributes highly towards electrical conductivity.
Impurity Level in p-type Semiconductor: In a p-type semiconductor, the impurity level appears close to the valence band. Therefore at ordinary temperature electrons acquire enough energy to move easily from the top of the valence band to the impurity level and leaves positive holes in the valence band which is free to move within the semiconductor and this thing contributes highly toward conductivity.
It is clear, therefore, that the addition of donor or acceptor impurity increases the conductivity above the intrinsic level of the semiconductor. In n-type material the majority carriers are electrons and minority carriers are holes while in the case of p-type material the situation is reversed.