Question

In the band structure of n-type semiconductor , the free electrons donated by impurity atoms occupy energy levels in

• A. the conduction band.
• B. the valence band.
• C. the band gap and are close to conduction band.
• D. the band gap and are close to valence band.

Hint:

Donor levels lie in the band gap just below the conduction band.

Answer 1

The Correct Option is C

Step 1: Compare impurity types:
Donor (n-type): extra electron, level just below the conduction band. Acceptor (p-type): hole-creating level just above the valence band.

Step 2: For n-type:
The donor level sits in the gap near the conduction band edge.

Step 3: Choose:
Option (C) states exactly this.

Final Answer:
Option (C). \[ \boxed{\text{Option (C)}} \]