To make n-type semiconductor, the dopants are
A. Boron
B. Antimony
C. Phosphorus
D. Aluminium
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B and C only
An n-type semiconductor is made by doping with a pentavalent (group 15) impurity. Four of its five valence electrons form bonds, and the fifth becomes a free electron, so the impurity acts as a donor.
(A) Boron — Incorrect. Boron is trivalent (group 13); it accepts an electron and makes a p-type semiconductor.
(B) Antimony — Correct. Antimony is pentavalent (group 15).
(C) Phosphorus — Correct. Phosphorus is pentavalent (group 15).
(D) Aluminium — Incorrect. Aluminium is trivalent (group 13), an acceptor impurity for p-type material.
NCERT (2026-27):
Summary – “… n-type semiconducting Si or Ge is obtained by doping with pentavalent atoms (donors) like As, Sb, P, etc., while p-type Si or Ge can be obtained by doping with trivalent atom (acceptors) like B, Al, In etc.”