In a p$^(+)-$n Si junction, the n $-$side has a donor concentration of $10^(16)$cm$^(-3).$ If n$\_($i$)=10^(10)$cm$^(-3),$ relative

dielectric constant $\backslash$epsi $\_($r$)=12$p$^(+)$means very

heavily doped. $($b$)$ under reverse bias the potential barrier height changes from V$\_(0)$ to V$\_(0)-$V$\_($R$),$ where

V$\_($R$)=-100$V$.($c$)$ dielectric constant $\backslash$epsi $=\backslash$epsi $\_(0)\backslash$epsi $\_($r$),$ where $\backslash$epsi $\_(0)$ is vacuum dielectric constant, $8\mathrm{.}85\backslash$times $10^(-12)($F$)/($m$).$