Question Detail
Question
Which of the following statements about doping semiconductors is true?
i. Doping of semiconductors improves its conductivity.
ii. Doping a semiconductor renders it totally immune to ambient temperature.
iii. Doping of semiconductor alters the composition of carriers in it.
i. Doping of semiconductors improves its conductivity.
ii. Doping a semiconductor renders it totally immune to ambient temperature.
iii. Doping of semiconductor alters the composition of carriers in it.
Correct Answer
Option C is the correct answer.
Detailed Explanation
Statement i: Doping involves adding impurities to a semiconductor, which increases the number of charge carriers (electrons or holes), thereby improving its conductivity. This statement is TRUE.Statement ii: Doping does not make a semiconductor totally immune to ambient temperature. Temperature still significantly affects the intrinsic carrier concentration and thus the conductivity. This statement is FALSE.Statement iii: Doping introduces donor or acceptor impurities, which changes the ratio of electron to hole concentrations, altering the composition of majority and minority carriers. This statement is TRUE.Therefore, statements i and iii are correct.
Hint
Consider the primary purpose and effects of doping on semiconductors. Does it make them perfect, or just modify their electrical properties?