Easy MCQ +4 / -1 PYQ · JEE Mains 2021

For extrinsic semiconductors; when doping level is increased;

  1. A Fermi-level of both p-type and n-type semiconductors will go upward for T &gt; T<sub>F</sub>K and downward for T &lt; T<sub>F</sub>K, where T<sub>F</sub> is Fermi temperature.
  2. B Fermi-level of p-type semiconductor will go upward and Fermi-level of n-type semiconductors will go downward
  3. C Fermi-level of p and n-type semiconductors will not be affected.
  4. D Fermi-level of p-type semiconductors will go downward and Fermi-level of n-type semiconductor will go upward. Correct answer

Solution

In n-type semiconductor pentavalent impurity is added. Each pentavalent impurity donates a free electron. So the Fermi-level of n-type semiconductor will go upward.<br><br>And In p-type semiconductor trivalent impurity is added. Each trivalent impurity creates a hole in the valence band. So the Fermi-level of p-type semiconductor will go downward.

About this question

Subject: Physics · Chapter: Electronic Devices · Topic: Semiconductors

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