# Fermi Level for Silicon

1. ### tot

43
what I've been told there is two groups of energy levels called the valence and the conduction band.

what is the fermi level for silicon?
how wide is the band gap for silicon?

Last edited: May 7, 2014
2. ### Bashkir

31
Well, if we are talking about intrinsic silicon (undoped silicon) then the fermi energy is directly in the center of the band gap. This means that the concentration of holes and electrons is equal. Doping the silicon will move the fermi energy towards the valence band or the conduction band depending on the doping.

The band gap for silicon is 1.12eV

$$E_f - E_i = kT ln\frac{n}{n_i}$$

3. ### tot

43
is 1.12eV the width of the band gap or the fermi level?
what is the fermi level for undoped silicon?

Last edited: May 7, 2014
4. ### Bashkir

31
That is the width of the band gap as I stated in the last post. The fermi level for undoped silicon lies directly inbetween the conduction band and the valence band. I have also provided you with the equation that you need to find the fermi level.

5. ### tot

43
i dont understand the equation. please explain how you find the fermi level

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