Consider a silicon $p-n$ junction with a uniform acceptor doping concentration of $10^{17} cm^{-3}$ on the $p$-side and a uniform donor doping concentration of $10^{16}cm^{-3}$ on the $n$-side. No external voltage is applied to the diode. Given: $kT/q = 26 \: mV$, $n_i = 1.5 \times 10^{10} cm^{-3}$ , $\epsilon_{Si} = 12 \varepsilon_0$, $\varepsilon_0 = 8.85 \times 10^{-14} F/m$, and $q = 1.6 \times 10^{-19} \: C$.
The charge per unit junction area($nC \: cm^{-2}$) in the depletion region on the $p$-side is _________