How do Intrinsic Semiconductors Work?
To understand the working mechanism of intrinsic semiconductors, we need to know the electronic configuration of their atoms.
The electronic configuration of silicon and germanium are:
1. Silicon –> 1s2 2s2 2p6 3s2 3p2
2. Germanium –> 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2
We can clearly see that the outermost shell is having 4 electrons. At 0 Kelvin, the semiconductor behaves like a pure insulator. Now, with the increase in the temperature, electrons gain enough energy to free from its shell and leave behind an empty place known as a hole. Thus, a free electron is produced along with a hole.This is the reason for the equal number of electrons and holes in intrinsic semiconductors.
What is Intrinsic Semiconductor ?
Intrinsic semiconductors are semiconductors that are pure i.e. it does not contain any impurity. Since it does not contain any impurity, the number of free electrons and the number of holes are equal. It is also known as an i-type semiconductor. The number of free electrons and the number of holes depends on the property of the material and does not depend on the doping.
For intrinsic semiconductors
n = p
where, n=number of electron, m=number of holes.
On the basis of electrical conductivity, materials are classified as:
- Conductors: Good conductors of electricity
- Insulators: Bad conductors of electricity
- Semiconductors: These materials have conductivity levels between those of conductors and insulators.
On the basis of the amount of doping, semiconductors are Classified as:
- Intrinsic Semiconductors
- Extrinsic Semiconductors
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