Consider a GaAs pn junction at T $=300$K$.$ The junction

capacitance at zero bias is C$(0),$ and the junction capacitance with a $10$ V reverse bias

is C$(10$ V$).$ The ratio of the capacitances is C$(0)/$C$(10$ V$)=3\mathrm{.}13.$ Only $20\%$ of the

depletion region lies in the p side of the junction.