Carrier types in p-type semiconductors: In p-type material, which species are the minority carriers under normal bias and temperature?

Introduction / Context:
Device behavior in diodes and transistors depends on majority and minority carriers in each region. Correctly identifying minority carriers is necessary for understanding recombination, diffusion currents, and the operation of PN junctions and BJTs (for example, base transport in a PNP device).

Given Data / Assumptions:

• p-type semiconductor doped with acceptors (for example, boron in silicon).
• Thermal equilibrium or small-signal operating conditions.
• No high-level injection that would alter carrier balances.

Concept / Approach:

Doping a semiconductor with acceptors creates an abundance of holes (majority carriers). The intrinsic carrier concentration ensures a smaller population of electrons remains; these are the minority carriers. Many junction phenomena, including reverse saturation current, are dominated by minority carrier behavior.

Step-by-Step Solution:

Verification / Alternative check:

PN junction equations (for example, reverse current proportional to minority carrier concentrations) and Hall effect measurements confirm carrier types in doped regions.

Why Other Options Are Wrong:

• Holes: majority, not minority, in p-type.
• Dopants: fixed ionized acceptor atoms are not mobile carriers.
• “Slower”: not a carrier type; mobility varies but does not define minority status.
• Excitons: bound electron-hole pairs, not the usual conduction carriers in bulk silicon devices.

Common Pitfalls:

• Assuming minority carriers are negligible; they dominate reverse currents and switching recovery.
• Confusing mobility with population; holes can have lower mobility but still be the majority.

Final Answer:

electrons