JEE MAIN - Physics (2021 - 25th February Evening Shift - No. 16)
For extrinsic semiconductors; when doping level is increased;
Fermi-level of both p-type and n-type semiconductors will go upward for T > TFK and downward for T < TFK, where TF is Fermi temperature.
Fermi-level of p-type semiconductor will go upward and Fermi-level of n-type semiconductors will go downward
Fermi-level of p and n-type semiconductors will not be affected.
Fermi-level of p-type semiconductors will go downward and Fermi-level of n-type semiconductor will go upward.
Explanation
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.
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.
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.
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