In a n-type semiconductor, which of the followingstatement is true? [NEET 2013]a)Electrons are minority carriers andpentavalent atoms are dopants.b)Holes are minority carriers and pentavalentatoms are dopants.c)Holes are majority carriers and trivalentatoms are dopants.d)Electrons are majority carriers and trivalentatoms are dopants.Correct answer is option 'B'. Can you explain this answer?

Question

Answer

Explanation:

An n-type semiconductor is formed by doping pentavalent impurities like arsenic, antimony, and phosphorus. These impurities have five electrons in their outermost shell. When they are added to the pure semiconductor, four of their five electrons are used to form covalent bonds with the neighboring atoms of the semiconductor, leaving one electron free. This free electron is responsible for conduction in the semiconductor, making it an n-type semiconductor.

Minority and Majority Carriers:

In an n-type semiconductor, the majority carriers are electrons, which are introduced by doping impurities. Minority carriers are the charge carriers that are present in a semiconductor in small concentrations. In the case of an n-type semiconductor, the minority carriers are holes, which are created due to the thermal excitation of electrons from the valence band to the conduction band.

Dopants:

Dopants are impurities that are intentionally added to a semiconductor to modify its electrical properties. In an n-type semiconductor, pentavalent impurities like arsenic, antimony, and phosphorus are used as dopants.

Correct Option:

Option (b) is correct because in an n-type semiconductor, holes are minority carriers, and pentavalent atoms are dopants.

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