Semiconductor carrier types: in which material are holes the minority carriers under normal doping and equilibrium conditions?

Introduction / Context:Knowing which carriers are majority and which are minority is crucial for understanding diode behavior, transistor action, and recombination processes. This question probes identification of minority carriers for a common doping type.

Given Data / Assumptions:

• Thermal equilibrium conditions.
• Standard n-type and p-type doping without high-level injection.
• No illumination or extreme temperature effects changing carrier populations drastically.

Concept / Approach:In n-type material, donor impurities add electrons, making electrons the majority carriers and holes the minority carriers. In p-type material, acceptor impurities create holes as majority carriers, making electrons the minority carriers. Intrinsic material has equal concentrations of electrons and holes.

Step-by-Step Solution:Step 1: Identify n-type doping adds electrons as majority carriers.Step 2: Recognize that the other carrier type (holes) becomes the minority.Step 3: Conclude that holes are minority carriers in n-type semiconductors.

Verification / Alternative check:Position of the Fermi level near the conduction band in n-type material reflects higher electron concentration and lower hole concentration, consistent with holes as minority carriers.

Why Other Options Are Wrong:

• Extrinsic: Generic term for doped semiconductors; does not specify majority type.
• Intrinsic: Electrons equal holes, so there is no minority in the sense of imbalance.
• p-type: Holes are majority there, not minority.
• None of the above: Incorrect because n-type is correct.

Common Pitfalls:Confusing majority and minority roles between n-type and p-type, or overlooking that illumination or injection can temporarily change populations; here we assume normal equilibrium.

Final Answer:n-type.