Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Semiconductors and Electronic Devices

Question:

A pure semiconductor germanium or silicon, free of every impurity is called intrinsic semiconductor. At room temperature, a pure semiconductor has very small number of current carriers (electrons and holes) .Hence its conductivity is low. When the impurity atoms of valance five or three are doped in a pure semiconductor, we get respectively n- type or p- type extrinsic semiconductor. In case of doped semiconductor ne.nh = ni2. Where ne and nh are the number density of electron and hole charge carriers in a pure semiconductor. The conductivity of extrinsic semiconductor is much higher than that of intrinsic semiconductor.

Which of the following statements is not true?

Options:

The resistance of intrinsic semiconductor decreases with increase of temperature

.Doping pure Si with trivalent impurities gives p- type semiconductors

The majority charge carriers in n- type semiconductors are holes.

A p-n junction can act as semiconductor diode.

Correct Answer:

The majority charge carriers in n- type semiconductors are holes.

Explanation:

$\text{The majority charge carriers in n- type semiconductors are electrons.}$