Question

Pure Si at 500 K has equal number of electron (n_e) and hole (n_h) concentrations of 1.5 x 10¹⁶ m^-3. Doping by indium increases n_h to 4.5 x 10²² m^-3. The doped semiconductor is of 

(a) p-type having electron concentration n_e = 5 x 10⁹ m^-3 

(b) n-type with electron concentration n_e = 5 x 10²² m^-3 

(c) p-type with electron concentration n_e = 2.5 x 10¹⁰ m^-3

(d) n-type with electron concentration n_e = 2.5 x 10²³ m^-3

Answer 1

The correct option is (a) p-type having electron concentration n_e = 5 x 10⁹ m^-3 

Explanation:

 p-type semiconductor is obtained when Si or Ge is doped with a trivalent impurity like aluminium (Al), boron (B). indium (In) etc,