Concept:Doping a tetravalent semiconductor with trivalent impurity atoms generates an excess of electron vacancies (holes) in the valence band, making holes the majority carriers while thermally generated conduction electrons remain the minority carriers.
Formula:$$p \gg n \quad \text{and} \quad p \cdot n = n_i^2$$
Solution:- Trivalent dopants (acceptors) create abundant holes without generating equal conduction electrons.
- Therefore, holes constitute the majority charge carriers, and electrons form the minority charge carriers.
Why other options are incorrect:- Option A: This describes an N-type semiconductor where electrons are the majority carriers.
- Option C: Positive ions are fixed dopant cores in the crystal lattice and are not mobile charge carriers.
- Option D: Protons are bound inside atomic nuclei and do not take part in electrical conduction in solids.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.