In $n$-type semiconductor when all donor states are filled, then the net charge density in the donor

Question

In $n$-type semiconductor when all donor states are filled, then the net charge density in the donor states becomes

Professor PC Thomas Classes · Answer

(b) : If all the donor states in $n$-type semiconductor are filled, the number of electrons in donor states will increase. Due to it, the charge density in donor states will become more than one.