A semiconductor is doped with phosphorous atoms as impurity. The impurity levels created in the semiconductor are close to the

• A

  top of the valence band
• Correct answer
  B

  bottom of the conduction band
• C

  bottom of the valence band
• D

  top of the conduction band

Solution

Phosphorous is a pentavalent impurity. So, resulting semiconductor is a $n$-type semiconductor. The energy band diagram of a $n$-type semiconductor is shown below
So, the energy levels of impurity atom created in the semiconductor are close to the bottom of the conduction band.

Hence, the correct answer is option: 'B'.