Practice portal › Semiconductor Electronics › Intrinsic and Extrinsic Semiconductors

For extrinsic semiconductors, when doping level is increased

Asked in JEE Main 25th Feb 2nd Shift 2021 · Doping and carrier concentration

• (1) Fermi-level of p-type semiconductors will go downward and Fermi-level of n-type semiconductor will go upward.
• (2) Fermi-level of p-type semiconductor will go upward and Fermi-level of n-type semiconductors will go downward.
• (3) Fermi-level of both p-type and n-type semiconductors will go upward for T>T_F K and downward for T<T_F K, where T_F is Fermi temperature.
• (4) Fermi-level of p and n-type semiconductors will not be affected.

Step-by-step solution

Why the other options are wrong

• (2) Reverses the directions: more acceptors pull the level towards the valence band.
• (3) Mixes in a metal concept; the shift here depends on dopant type, not on a Fermi temperature.
• (4) The Fermi level position depends on carrier densities, which doping changes.

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.