Question

When a pentavalent impurity is added to a pure semiconductor, it becomes *

Answer 1

Answer:

The pentavalent impurity is added to pure semiconductor, then it become :

Answer 2

Answer:

When a pure semiconductor is mixed with a pentavalent impurity, then it becomes an n-type semiconductor.

Explanation:

• The pure semiconductor has 4 valence electrons, so it does not conduct electricity.
• To make a semiconductor conduct electricity, it is doped with impurities.
• A pentavalent impurity contains 5 valence shell electrons.
• When this impurity is doped with a semiconductor, then the 4 valence electrons of the semiconductor form a covalent bond with the 4 valence electrons of the impure element.
• During this bonding, one valence electron of the impurity is left unbonded.
• This extra electron starts moving and thus the semiconductor doped with pentavalent impurity starts conducting electricity.

Since pentavalent impurity provides an electron, a negative charge carrier to the semiconductor, it is known as an n-type semiconductor.