Difficulty: Easy
Correct Answer: Incorrect
Explanation:
Introduction / Context:Doping determines whether a semiconductor conducts primarily via electrons (n-type) or holes (p-type). A precise understanding of “donors” and “acceptors” helps avoid conceptual errors in device analysis and design.
Given Data / Assumptions:
Concept / Approach:n-type material is made by adding donor impurities that have five valence electrons—one more than silicon’s four. This extra electron is weakly bound and becomes a mobile conduction electron, increasing electron concentration above hole concentration. Saying “add material with electron holes” actually describes p-type (acceptor) doping, where trivalent atoms create a deficiency of electrons (holes) that act as majority carriers.
Step-by-Step Solution:
Identify goal: n-type → electrons are majority carriers.Select dopant: donors (group 15) contribute extra electrons.Mechanism: donor ionization releases electrons into the conduction band.Conclusion: the statement mixes up donors and acceptors; it is incorrect.Verification / Alternative check:Hall effect measurements on n-type samples show negative Hall coefficient, confirming electrons as majority carriers due to donor doping.
Why Other Options Are Wrong:
Correct / temperature qualifiers / compound-only caveats: the fundamental donor/acceptor roles remain the same across standard semiconductors.Common Pitfalls:Using “holes” as a generic synonym for carriers; mixing up which dopants create electrons versus holes.
Final Answer:Incorrect
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