$kT=0\mathrm{.}026eV$ at $300K,S{i}_i={10}^{10}c{m}^{-3}$ at $300K,S{i}_g=1\mathrm{.}1eV,q=1\mathrm{.}6{10}^{-19}C,h=6\mathrm{.}63{10}^{-34}J-s,{}_0=8\mathrm{.}85{10}^{-14}\frac{F}{c}m,$ Relative permittivity of $Si=11\mathrm{.}8,c=3{10}^{10}c\frac{m}{s},I_0=qA(D_p\frac{p_n}{L_p}+D_n\frac{n_p}{L_n})$

$2.(57$ p$)$ An abrupt p$-$n junction has the following properties at