Ionized dopants and quasi-fermi level

[Pete99]

Hello all,

I have a question regarding quasi-fermi levels that probably some one can help me to understand.

In a pn junction in equilibrium we can calculate the number of ionized dopants from the distance between the ionization energy of the dopants and the fermi level.

Now, if we apply a voltage, we can in general define two different quasi-fermi level for holes and electrons. How can we calculate the number of ionized dopants now?

Thanks for any help,

 

[Pete99]

Any insight?