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In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always present
- a)such that number of holes is greater than the number of electrons
- b)in equal numbers
- c)such that number of electrons is greater than the number of holes
- d)none of these
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
In a pure, or intrinsic, semiconductor, valence band holes and conduct...
Explanation:An intrinsic semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure semiconductor without any significant dopant species present. The number of charge carriers is therefore determined by the properties of the material itself instead of the amount of impurities. In intrinsic semiconductors the number of excited electrons and the number of holes are equal: n = p.
Most Upvoted Answer
In a pure, or intrinsic, semiconductor, valence band holes and conduct...
Understanding Intrinsic Semiconductors
In intrinsic semiconductors, the behavior of charge carriers is fundamental to their electronic properties. Here’s a detailed explanation of why the number of holes equals the number of electrons.
Charge Carriers in Semiconductors
- Electrons and Holes: In a semiconductor, electrons can move freely in the conduction band, while holes (the absence of an electron) exist in the valence band.
- Intrinsic Nature: Intrinsic semiconductors are pure materials without any significant impurities. The electrons in the conduction band come from the valence band when thermal energy breaks the covalent bonds.
Equal Numbers of Electrons and Holes
- Generation of Electron-Hole Pairs: When an electron is excited from the valence band to the conduction band, it leaves behind a hole. This process ensures that for every electron promoted to the conduction band, there is a corresponding hole created in the valence band.
- Thermal Equilibrium: In an intrinsic semiconductor at thermal equilibrium, the generation of electron-hole pairs is balanced by their recombination. Hence, the number of electrons (n) in the conduction band equals the number of holes (p) in the valence band, leading to the equation n = p.
Conclusion
- The intrinsic nature of semiconductors guarantees that the number of conduction electrons and valence band holes are equal. This balance is a defining characteristic of pure semiconductors, making option 'B' (in equal numbers) the correct answer.
Understanding this fundamental concept is crucial for grasping the behavior of semiconductors in electronic devices.
In intrinsic semiconductors, the behavior of charge carriers is fundamental to their electronic properties. Here’s a detailed explanation of why the number of holes equals the number of electrons.
Charge Carriers in Semiconductors
- Electrons and Holes: In a semiconductor, electrons can move freely in the conduction band, while holes (the absence of an electron) exist in the valence band.
- Intrinsic Nature: Intrinsic semiconductors are pure materials without any significant impurities. The electrons in the conduction band come from the valence band when thermal energy breaks the covalent bonds.
Equal Numbers of Electrons and Holes
- Generation of Electron-Hole Pairs: When an electron is excited from the valence band to the conduction band, it leaves behind a hole. This process ensures that for every electron promoted to the conduction band, there is a corresponding hole created in the valence band.
- Thermal Equilibrium: In an intrinsic semiconductor at thermal equilibrium, the generation of electron-hole pairs is balanced by their recombination. Hence, the number of electrons (n) in the conduction band equals the number of holes (p) in the valence band, leading to the equation n = p.
Conclusion
- The intrinsic nature of semiconductors guarantees that the number of conduction electrons and valence band holes are equal. This balance is a defining characteristic of pure semiconductors, making option 'B' (in equal numbers) the correct answer.
Understanding this fundamental concept is crucial for grasping the behavior of semiconductors in electronic devices.
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In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? for Class 12 2026 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 12 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer?.
In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? for Class 12 2026 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 12 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer?.
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