$2)$A$$Si$$p$-$n $$junction has a cross$-$sectional area of$0\mathrm{.}001$cm$2,$boron doping on $$one side at$1016$cm$-3,$and

phosphorous doping on $$the other side at$31017$cm$-3.$

For Si$,$the electron mobility is$1350$cm$2$Vs$,$the hole mobility is$480$cm$2$Vs$,$the charge carrier lifetime is$2$s$,$

the intrinsic charge carrier density is$1\mathrm{.}51010$cm$-3,$and the dielectric constant is$11\mathrm{.}8.$

What is $$the contact potential?

What are the depletion region widths on $$the p$-$side and n$-$side and the current for a forward bias voltage of$0\mathrm{.}7$V$.$