Suppose I have a n-type semiconductor whose fermi-level lies (say) 0.2 eV below the conduction band. Why would this level change if I changed the doping by making the donor concentration (say) 4 times the original value?
And what does it even mean? Does this mean that chemical potential also changes ? (I guess it, probably, does but what it means?)
Also could we estimate how would it change in some approximate way?