Difference between intrinsic and extrinsic semiconductors
We have already discussed about the concept of semiconductors, their types: intrinsic and extrinsic semiconductors and further types of extrinsic semiconductors that are n type semiconductors and p type semiconductors. Today we will discuss the difference between intrinsic and extrinsic semiconductors on point to point basis:
It is pure semi-conducting material and no impurity atoms are added to it.
Examples: crystalline forms of pure silicon and germanium.
The number of free electrons in the conduction band and the no. of holes in valence band is exactly equal and very small indeed.
Its electrical conductivity is low.
Its electrical conductivity is a function of temperature alone.
It is prepared by doping a small quantity of impurity atoms to the pure semi-conducting material.
Examples: silicon “Si” and germanium “Ge” crystals with impurity atoms of As, Sb, P etc. or In B, Aℓ etc.
The number of free electrons and holes is never equal. There is excess of electrons in n-type semi-conductors and excess of holes in p-type semi-conductors.
Its electrical conductivity is high.
Its electrical conductivity depends upon the temperature as well as on the quantity of impurity atoms doped the structure.
These are the differences between intrinsic and extrinsic semiconductors. If you know more, then please discuss. You can also read my articles about semiconductor and difference between n type and p type semiconductors.