The Fermi level is the highest energy level that an electron can occupy at absolute zero temperature and plays a crucial role in determining the thermal and electrical properties of solids, including semiconductors
. It is a thermodynamic quantity usually denoted by ยต or EF and represents the electron population at energy levels, consequently determining the conductivity of materials
. In semiconductors, the Fermi level is influenced by factors such as doping and temperature
. The position of the Fermi level in relation to the band energy levels is a crucial factor in determining the voltage and flow of charge in an electronic circuit
. For intrinsic semiconductors, the Fermi level lies close to the valence band
. In doped semiconductors, such as p-type and n-type, the Fermi level is shifted by the impurities, illustrated by their band gaps
. The Fermi level is essential for understanding the band theory of solids and the behavior of electrons in semiconductors. It helps explain why electrons do not contribute significantly to thermal conductivity and electrical conductivity, as only a tiny fraction of the electrons in a material are within the thermal energy kT of the Fermi level at ordinary temperatures
