What is the difference between an intrinsic and extrinsic semi conductor material? What is doping?

Intrinsic semiconductors: -

These are pure semi-conducting materials and no impurity atoms are added to it.

For example: The crystals of pure like germanium and silicon are considered as Intrinsic Semiconductor.

Properties: 1. In intrinsic semiconductor, the number of electrons is equal to the number density of holes. i.e., ne=nh. 2. The electrical conductivity is low. 3. The electrical conductivity of intrinsic semiconductors depends on their temperatures.

Extrinsic semiconductors:-

When some impurity is added in the intrinsic semiconductor, extrinsic semiconductors can be produced.

Properties: 1. In extrinsic semiconductor, the number density of electrons is not equal to the number density of holes. i.e., ne is not equal to nh. 2. The electrical conductivity is high. 3. The electrical conductivity depends on the temperature and the amount of impurity added in them.

Doping:-

Doping is the process of adding impurities to intrinsic semiconductors to change their properties. As we know Silicon and Germanium are known as intrinsic semiconductors. Mostly Trivalent and Pentavalent elements are used to dope these elements.

1- When a intrinsic semiconductor is doped with Trivalent impurity it becomes a P-Type semiconductors. The P stands for Positive, which means the semiconductor is rich in holes or Positive charged ions.

2-When we dope intrinsic material with Pentavalent impurities we get N-Type semiconductor, where N stands for Negative. N-type semiconductors have Negative charged ions or in other words have excess electrons.

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