bluejay27 said:Where does the fermi level lie at? I have an understanding that at absolute zero it would be lying halfway the band gap. Shouldn't it be lying at the top part of the valence band?
The Fermi Level is located within the energy band gap of an atom, specifically at the highest occupied energy level at absolute zero temperature. This means that it is the energy level at which electrons have a 50% probability of being occupied.
As temperature increases, the Fermi Level also increases. This is because at higher temperatures, more energy is available for electrons to occupy higher energy levels, causing the Fermi Level to shift towards higher energies.
In semiconductors, the Fermi Level lies close to the middle of the energy band gap. This means that at room temperature, there is a small number of electrons in the conduction band and a small number of holes in the valence band. This allows semiconductors to have properties of both conductors and insulators, making them useful in electronic devices.
Doping, which is the intentional addition of impurities to a semiconductor, can significantly alter the Fermi Level. N-type doping, where atoms with extra electrons are added, lowers the Fermi Level, while P-type doping, where atoms with missing electrons are added, raises the Fermi Level.
Yes, the Fermi Level plays a crucial role in determining the electrical conductivity of a material. In metals, the Fermi Level lies within the conduction band, allowing for a high number of free electrons and high conductivity. In insulators, the Fermi Level lies within the valence band, and there are no free electrons, resulting in low conductivity. In semiconductors, the position of the Fermi Level can be manipulated to control the conductivity of the material.