Name: Energy Band Gap
Uploaded: 2019-07-19
Duration: 5 min 21 s
Description: We know that certain materials conduct electricity whereas some don’t. Has it got anything to do with their energy bandgap? Let’s find out in this video.

Question

Distinguish between a metal, an insulator and a semiconductor.

Accepted Answer

Metals have either a partially filled conduction band or a partially empty valence band. As electrons acquire energy above the Fermi level in the conduction band, they act as free electrons and transfer to higher energy levels. There is no forbidden energy gap in metals, and the amount of electrons available for conduction is increasing, increasing its conductivity.

The valence band is fully filled in insulators, while the conduction band is empty. As a consequence, there is a significant energy difference. There is no transfer of electrons from the valence band to the conduction band since the energy difference between the conduction band and the valence band is greater.

The valence band of a semiconductor is fully packed with electrons, while the conduction band is empty. The energy difference between the bands is smaller. Room temperature must be preserved for electrons to move from the valence band to the conduction band. There is no electron transfer from the valence band to the conduction band when the temperature is $0 K .$

Distinguish between a metal, an insulator and a semiconductor.

Important Questions on Solids

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