Which one of the following statements is false?
- Pure Si doped with trivalent impurities gives a p-type semiconductor.
- Majority carriers in a n-type semiconductor are holes.
- Minority carriers in a p-type semiconductor are electrons.
- The resistance of intrinsic semiconductor decreases with increase of temperature.
Answer
(2) Majority carriers in a n-type semiconductor are holes.
Solution
(1) True: a trivalent dopant (B, Al, In) creates holes ⇒ p-type.
(2) False: in an n-type semiconductor (pentavalent dopant) the majority carriers are electrons; holes are the minority carriers.
(3) True: in a p-type semiconductor holes are majority and electrons are minority carriers.
(4) True: with rise in temperature more electron–hole pairs are generated, so the resistance of an intrinsic semiconductor decreases.
Answer: (2)