Question

For a semiconductor to be called as p-type semiconductor, which one of the following element impurities are added to a pure semiconductor ?
1. Phosphorus
2. Arsenic
3. Antimony
4. Boron

Answer 1

Correct Answer - Option 4 : Boron

CONCEPT:

• The material which is not a good conductor or a good insulator is called a semiconductor.
• For example Silicon
• The charge carriers which are present in more quantity in a semiconductor compared to other particles are called the majority charge carrier.

• The impurity atoms added are called dopants and semiconductors doped with the impurity atoms are called extrinsic or doped semiconductors.
• The pure form of semiconductor is called an intrinsic semiconductor.

 

There are two types of semiconductors:

P-type semiconductor:

• The semiconductor having holes as majority charge carriers and electrons as a minority charge carrier is called a P-type semiconductor.
• When a trivalent impurity is doped in intrinsic semiconductors then we got P-type semiconductors. For Example: Boron, gallium, indium 

 

N-type semiconductor:

• The semiconductor having electrons as majority charge carriers and holes as a minority charge carrier are called N-type semiconductors.
• When a pentavalent impurity is doped in intrinsic semiconductors then we got N-type semiconductors. For Example: Arsenic

 

EXPLANATION:

When a trivalent impurity is added an intrinsic semiconductor then a P-type semiconductor is formed and when a pentavalent impurity is added in intrinsic semiconductor then an N-type semiconductor is formed. So option 3 is correct.