Question

A donor impurity results in

• A. conduction band just above the filled valence band
• B. holes as majority carriers and electrons as minority carriers
• C. production of n-type semiconductor
• D. production of p-type semiconductor

Hint:

Remember: Donor impurities donate free electrons, resulting in an n-type semiconductor.

Answer 1

The Correct Option is C

Step 1: Understanding donor impurities.
Donor impurities are pentavalent atoms such as phosphorus, arsenic, or antimony, which are added to a pure semiconductor like silicon or germanium. These atoms have five valence electrons, one more than required for covalent bonding.

Step 2: Effect on charge carriers.
The extra electron provided by the donor impurity becomes free to move and contributes to electrical conduction. Hence, electrons become the majority charge carriers, while holes become minority carriers.

Step 3: Final conclusion.
Since donor impurities increase the number of free electrons, they lead to the formation of an n-type semiconductor.