GATE EC 2017 Set 1 Q10 — Electronic Devices

An $n^+-n$ Silicon device is fabricated with uniform and non-degenerate donor doping concentrations of $N_{D1}=1\times 10^{18}cm^{-3}$ and $N_{D2}=1\times 10^{15}cm^{-3}$ corresponding to the $n^+$ and $n$ regions respectively. At the operational temperature $T$, assume complete impurity ionization. $kT/g=25mV$, and intrinsic carrier concentration to be $n_{i}=1\times 10^{10}cm^{-3}$ .What is the magnitude of the build-in potential of this device?