Correct Answer - Option 4 :
Little current conduction
Intrinsic semiconductor: It is a crystal having all atoms of the same nature i.e. extremely pure semiconductor is called intrinsic semiconductor.
Example: pure silicon, germanium.
- At room temperature (300 Kelvin), the electrons in the valence band are moved to the conduction band and little current flow.
- When an electron leaves the valence band it creates a vacancy known as a hole. A hole attracts electrons as it is positively charged.
- In intrinsic semiconductor number of free electrons is equal to the number of holes. i.e. ne = nh
- When current is passed through a material containing free electrons, the current is conducted, and it is known as current due to electrons (Ie).
- Similarly, when a current is passed through a material it can be conducted due to holes and it is known as current due to holes (Ih).
The total current passing through intrinsic semiconductors is given by:
I = Ie + Ih
