Fermi Energy level with respect to band gap energy

[Matt1234]

Homework Statement

Calculate Efi with respect to the center of the bandgap in silicon for t= 200, 400, 600 kelvin.

Homework Equations

ni = Nc e^-((Ec- Ef)/(kt))

k = boltzman constant
t= temperature in kelvin
Ec = energy level of the conduction band
ef= fermi energy level
ni= carrier concentration
Nc = densitiy of states in conduction band

The Attempt at a Solution

Im not sure how to approach this problem, please help.

 

[HunterDX77M]

You should have been given all the other variables to be able to solve this. Do you know the concentration and the density of states?