Concept:Acceptor impurities are trivalent atoms (e.g., Boron, Aluminium, Gallium, Indium) having three valence electrons. They accept an electron from an adjacent Si-Si bond, creating a vacancy or 'hole' in the valence band.
Formula:$$\text{Acceptor Doping: } \text{Group III Dopant} \implies \text{Holes } (p \approx N_A)$$
Solution:- Acceptor atoms accept electrons to complete covalent bonds, creating mobile holes in the valence band.
- The dopant atom itself becomes an immobile negative ion, while the created hole acts as a mobile positive charge carrier.
Why other options are incorrect:- Option A: Free electrons are supplied by donor (pentavalent) impurities.
- Option B: Negative ions are fixed lattice sites, not mobile charge carriers.
- Option D: Positive ions are formed when donor atoms lose electrons; they are immobile.
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