Question

Write a short note on p-type semiconductor.

Answer 1

Hint: A semiconductor has its conduction values between conductor and an insulator. The semiconductor in the pure form is known as intrinsic semiconductor. If the intrinsic semiconductor is doped with an electron acceptor in order to make it as a p-type semiconductor. The electron acceptor is responsible for the formation of a hole by accepting an electron from the lattice.

Complete answer:
p-type semiconductors conduct due to the present of holes which are formed by doping them with trivalent impurities.
In this type, the valence shell consists of three electrons and requires one more electron.
This is possible by sharing the electron. As it is accepting electrons it is generally referred to as acceptor. The acceptor impurities are Boron, indium, gallium. Once these are added to either silicon or germanium p-type semiconductors are formed.
Considering this concept let us as boron is trivalent impurity in silicon semiconductor.
As silicon has four valence electrons to share and form bonds with valence electrons of boron. But boron has only three valence electrons Then the absence of a fourth electron or the vacancy of the electron is termed as a hole.
It indicates that one electron is accepted by the boron atom. The vacancy or the need of electrons can be fulfilled.

This is how conduction and formation take place in case of p-type semiconductor.

Note:
The semiconductor type in which electrons are majority charge carriers are known as n-type semiconductor. They also come as both intrinsic form and extrinsic form.
When an external voltage is applied across a p-n junction diode, it is required to overcome a threshold voltage which is different for every semiconductor material. Eventually a barrier potential is seen to develop at the junction of the p-n junction diode.