Question

For a p-type semiconductor, which of the following statements is true ?

• A. Holes are the majority carriers and pentavalent atoms are the dopants.
• B. Electrons are the majority carriers and pentavalent atoms are the dopants.
• C. Electrons are the majority carriers and trivalent atom >re the dopants.
• D. Holes are the majority carriers and trivalent atoms are the dopants.

Answer 1

The Correct Option is D

To understand the nature of a p-type semiconductor, let's explore the characteristics and implications of doping in semiconductors:

1. Concept of Doping: Doping is the process of adding impurities to a semiconductor to change its electrical properties. The two main types of dopants are pentavalent (5 valence electrons) and trivalent (3 valence electrons) atoms.
2. P-Type Semiconductor: In a p-type semiconductor:
   • Trivalent atoms are used as dopants. Common examples are boron (B) or gallium (Ga).
   • These dopants introduce "holes" in the semiconductor's structure. A hole is essentially the absence of an electron and can move through the material, contributing to electrical conduction.
   • Majority Carriers: In a p-type semiconductor, holes are the majority carriers, meaning they are the primary charge carriers that facilitate electrical conduction.
3. Rule Out Other Options:
   • Option 1: "Holes are the majority carriers and pentavalent atoms are the dopants." - Pentavalent atoms create n-type semiconductors, not p-type.
   • Option 2: "Electrons are the majority carriers and pentavalent atoms are the dopants." - This describes an n-type semiconductor, not p-type.
   • Option 3: "Electrons are the majority carriers and trivalent atoms are the dopants." - Trivalent atoms lead to holes being the majority carriers, not electrons.
4. Conclusion: Thus, for a p-type semiconductor, the correct statement is: "Holes are the majority carriers and trivalent atoms are the dopants."

Correct Answer: Holes are the majority carriers and trivalent atoms are the dopants.

Tip: This type of question is common in exams to test your understanding of semiconductor physics. Always remember that 'p' in p-type can hint towards 'positive' holes being majority carriers.