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⚛️ Physics  ·  Semiconductor Electronics  ·  NEET & JEE

The depletion approximation in p-n junction analysis assumes:

Answer: Complete ionization within depletion region and zero carriers (sharp boundary).

  • A A gradual, smoothly varying doping profile across the junction
  • B Complete ionization within depletion region and zero carriers (sharp boundary)
  • C A significant population of mobile carriers within the depletion region
  • D An intrinsic, undoped semiconductor on both sides of the junction

Correct answer: B. Complete ionization within depletion region and zero carriers (sharp boundary)

Explanation: Depletion approximation: ionized donors/acceptors present in depletion region; mobile carrier density negligible. Creates abrupt space charge regions.

Conductorconduction bandvalence bandbands overlapSemiconductorconduction bandvalence bandsmall gap (~1 eV)Insulatorconduction bandvalence bandlarge gap(> 3 eV)

Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.

Concept context

Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.

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