Question

In a P-type semiconductor, the acceptor impurity is:

• A. Just above the valence band
• B. Just below the conduction band
• C. Just above the conduction band
• D. Just below the valence band

Hint:

P-type semiconductors are doped with elements that create holes by accepting electrons, thus allowing current flow via hole conduction.

Answer 1

The Correct Option is D

Step 1: P-type semiconductor formation
A P-type semiconductor is formed by doping a pure semiconductor (like Si or Ge) with trivalent impurity atoms such as boron, aluminium, or gallium. These impurity atoms have one electron less than the host atoms, creating holes as majority charge carriers.

Step 2: Energy level formation
When acceptor impurities are added, they introduce an acceptor energy level in the forbidden energy gap. This level lies slightly above the valence band.

Step 3: Electron transition
Electrons from the valence band can easily jump into the acceptor level, leaving behind holes in the valence band, which act as majority carriers.

Final Conclusion:
Thus, in a P-type semiconductor, the acceptor energy level is located just above the valence band.