The impurity level in a semiconductor is about _______ of the pure semiconductor.
Right Answer is:
1 atom for 108 atoms
The impurity level in a semiconductor is about 1 atom for 108 atoms of the pure semiconductor.
Impurity Levels: An intrinsic semiconductor becomes an extrinsic semiconductor when a small amount of impurity is added to the given sample. The impurity creates new quantum states in the forbidden energy gap.
The amount and type of such impurities have to be closely controlled during the preparation of extrinsic semiconductors. Generally, one impurity atom is added to 108 atoms of a semiconductor.
Thus, a semiconductor to which an impurity at a controlled rate is added to make it conductive is known as an extrinsic semiconductor.