JEE Main202125 Feb 2021Evening ShiftPhysicsSemiconductorsActual
For extrinsic semiconductors; when doping level is increased;
Options
- AFermi-level of p and n - type semiconductors will not be affected.
- BFermi-level of p -type semiconductor will go upward and Fermi-level of n -type semiconductors will go downward
- CFermi-level of both p-type and n-type semiconductors will go upward for T > T F   K and downward for
- DFermi-level of p - type semiconductors will go downward and Fermi-level of n - type semiconductor will go upwa
Correct answer
D. Fermi-level of p - type semiconductors will go downward and Fermi-level of n - type semiconductor will go upwa
Step-by-step 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. & 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.