Table of Contents
Why Fermi level is close to valence band?
The addition of trivalent impurity creates large number of holes in the valence band. At room temperature, the number of holes in the valence band is greater than the number of electrons in the conduction band. Therefore, the Fermi level in the p-type semiconductor lies close to the valence band.
In which of the following the Fermi energy level is closer to the valence band?
a p-type semiconductor
Fermi energy level in a p-type semiconductor: Therefore, the Fermi level is closer to the valence band in a p-type semiconductor.
What does Fermi level in band gap mean?
The Fermi Level is the energy level which is occupied by the electron orbital at temperature equals 0 K. There is a gap between the valence and conduction band called the energy gap; the larger the energy gap, the more energy it is required to transfer the electron from the valence band to the conduction band.
How does Fermi level depend on carrier concentration?
The number of holes in the valence band is depends on effective density of states in the valence band and the distance of Fermi level from the valence band. For an intrinsic semiconductor, the electron-carrier concentration is equal to the hole-carrier concentration.
Why does Fermi energy level in an n-type semiconductor shift towards the conduction band?
It has to shift towards conduction band in an n-type semiconductor (extrinsic semiconductors with added doping impurities which are donors i.e. impurities which give additional electrons to the system) where the number of electrons n is higher than the number of holes (n>p).
What is meant by valence band and conduction band?
In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. On a graph of the electronic band structure of a material, the valence band is located below the Fermi level, while the conduction band is located above it.