Classification Of Metals Conductors And Semiconductors

To understand the characteristics of a p-type semiconductor, it is essential to comprehend the role of dopants and charge carriers in semiconductors.

Explanation:

• A p-type semiconductor is created by introducing impurities into a semiconductor, specifically trivalent elements (such as Boron, Gallium, Indium) into a silicon or germanium lattice.
• The trivalent atoms have three valence electrons and when they replace an atom in the lattice (usually silicon, which has four valence electrons), they form three covalent bonds with neighboring silicon atoms, leaving one bond incomplete. This incomplete bond effectively creates a 'hole', which is considered a positive charge carrier.
• The presence of these holes (created due to a deficiency of electrons) means that the number of holes increases significantly and holes become the majority charge carriers.
• In contrast, the electrons become the minority carriers in a p-type semiconductor.

Option Analysis:

1. Holes are the majority carriers and trivalent atoms are the dopants. This statement is correct, as explained above.
2. Holes are the majority carriers and pentavalent atoms are the dopants. This is incorrect. Pentavalent atoms such as phosphorus, arsenic are used for n-type semiconductors, where electrons are the majority carriers.
3. Electrons are the majority carriers and pentavalent atoms are the dopants. This describes an n-type semiconductor, not a p-type.

Conclusion: The correct answer is: Holes are the majority carriers and trivalent atoms are the dopants.