question_answer

Energy gap of a semiconductor is of the order of:

A)  1 eV                                     

B)  10 eV

C)  0.1 eV                                 

D)  none of these

Correct Answer: A

Solution :

                 When an impurity atom with 3 valence electrons   is   introduced   is   a   pure semiconductor. All the three of its valence electrons form covalent bonds with one each valence electron of the nearest pure semiconductor (say germanium) while one is not able to form a bond, giving rise to hole which acts as charge carrier in a p-type semiconductor crystal.