JEE Main · 2023 · 01 Feb 2023 · Shift 1 · Chapter_pending

In an intrinsic semiconductor the electrons and holes are equal in number, so the Fermi level settles midway between the valence and conduction bands. Donor atoms in an $n$-type material supply extra electrons and raise the Fermi level close to the conduction band, while acceptor atoms in a $p$-type material create holes that pull the Fermi level down near the valence band. In a metal the conduction band is only partly filled, so the Fermi level lies within the conduction band itself. Hence the intrinsic semiconductor goes with a Fermi level in the middle of the two bands, the $n$-type with a Fermi level near the conduction band, the $p$-type with a Fermi level near the valence band, and the metal with a Fermi level inside the conduction band.