Silicon can be doped using one of the following elements as dopant :
(A) Arsenic
(B) Indium
(C) Phosphorus
(D) Boron
To get n-type semiconductor, the dopants that can be used are ___________________.
Fill in the blank with the correct answer from the options given below.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) and (C) only
An n-type semiconductor is made by doping silicon (valency 4) with a pentavalent impurity: four of its electrons form covalent bonds and the fifth becomes a free electron, so the impurity acts as a donor.
(A) Arsenic — group 15, pentavalent, a donor. It gives n-type.
(B) Indium — group 13, trivalent, an acceptor. It gives p-type.
(C) Phosphorus — group 15, pentavalent, a donor. It gives n-type.
(D) Boron — group 13, trivalent, an acceptor. It gives p-type.
So only (A) and (C) can be used.
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.”