Question

In an n-type semiconductor, majority charge carriers are
A) Electrons
B) Neutrons
C) Holes
D) Protons

Answer 1

Semiconductor is a material that has a conductivity between conductor and insulator. Two types of semiconductors are here, one is a pure(intrinsic) semiconductor and another is an impure(extrinsic) semiconductor. This extrinsic semiconductor is two types, one is a p-type semiconductor, another is an n-type semiconductor. Pure semiconductors are silicon (Si), germanium(Ge), etc.

Complete step by step answer:
An n-type semiconductor is made by doping some impure substances of valence 5 (As) with a pure semiconductor to raise it’s conductivity many times. Here the majority charge carrier is the electron(negative charge) and the minor charge carrier is the hole(positive charge).

A p-type semiconductor is made by doping some impure substances of valence 3 (B) with a pure semiconductor to raise it’s conductivity many times. Here the majority carrier is the hole (positive charge) and the minor carrier is the electron (negative charge).

Now we consider the given options,
Option A – electrons- the number density of electrons in an n-type semiconductor is high.so, the major carrier of n-type semiconductor is an electron.
Option B- neutrons- it is present in the nucleus, the charge is zero. It does not affect conductivity.
Option C- holes- there are a few numbers of holes present in an n-type semiconductor that means the number density of hole is lesser. So, this can not be a major carrier.
Option D- protons- it is also present in the nucleus, positively charged. it is not a part of conductivity.

Hence, the option (A) is the correct one.

Notes:
A process of adding substances with the pure semiconductor material is known as doping.
Adding some arsenic(As), phosphorus(P) with pure silicon, and germanium we get an n-type semiconductor. Here the majority charge carrier is an ‘electron’ and the minor charge carrier is the ‘hole’.
Adding some boron(B), aluminum (Al) with silicon and germanium, we get a p-type semiconductor. Here the major carrier is the ‘hole’ and the minor carrier is the ‘electron’.
Major charge carriers are the more abundant charge carriers. In an n-type semiconductor electron is more than the holes.