A silicon sample contains $1016$ cm $-3$ of phosphorous. Later, it is doped with $2*1017$ cm $-3$ of

boron. At this time, both phosphorous and boron atoms coexist in the silicon sample.

Suppose Ni $=1\mathrm{.}5*1010$ cm $-3,$ T $=300$K$,$ and Eg $=1\mathrm{.}1$e