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JAMB Physics 2009 Question 50

Question 50

Electronics

When a pentavalent impurity is added to a pure semiconductor, it becomes

  1. A.a p-type semiconductor.
  2. B.an n-type semiconductor.
  3. C.an insulator.
  4. D.an intrinsic semiconductor.
Show the answer and explanation

Answer: B (an n-type semiconductor.)

Explanation

A pentavalent atom has five valence electrons; one is left free, giving extra negative carriers, so the material becomes n-type.