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 n-type and p-type semiconductors.

Accepted Answer

An intrinsic semiconductor is doped with impurities to make it more conducting and an extrinsic semiconductor is formed. They are divided into two named n-type semiconductors and p-type semiconductors based on the valency of the atom used for doping. The difference between them are explained below.

When a trivalent impurity is doped into an intrinsic semiconductor, a p-type semiconductor is formed. It's mixed with an intrinsic semiconductor to make it more conductive. Boron, gallium, indium, aluminium, and other trivalent elements are examples of acceptor impurities. Majority charge carriers are holes and minority charge carriers are electrons. The acceptor energy level is close to the conduction band.

A small amount of pentavalent impurity is added to intrinsic germanium to produce an n-type semiconductor. These delocalised electrons increase the conductivity of doped germanium. Silicon doped with electron-rich impurity is referred to as an n-type semiconductor because the negatively charged electron induces an increase in conductivity. Arsenic, and phosphorus are common examples of this type of donor impurities. Majority charge carriers are electrons and minority charge carriers are holes.The donor level is close to valence band.

Distinguish between n-type and p-type semiconductors.

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