where is fermi energy?

[PZ]

"An n-type sample of silicon has a uniform density Nd= 10e16
atomes cm(-3) of arsenic. Find out the temperature at which half the
impurity atoms are ionized. Assume that all mobile electrons and holes
come from dopant impurities".

this is the question.

I was told the fermi level is about Ed, which is 0.05 below Ec. why is
fermy at Ed?


thanks

 

[Pooh Bear]

"An n-type sample of silicon has a uniform density Nd= 10e16
atomes cm(-3) of arsenic. Find out the temperature at which half the
impurity atoms are ionized. Assume that all mobile electrons and holes
come from dopant impurities".

this is the question.

I was told the fermi level is about Ed, which is 0.05 below Ec. why is
fermy at Ed?

Homework was it ?

Graham