Potential across the $p$ - $n$ junction varies symmetrically linear, having $p$-side negative and $n$-side positive. In a forward biased $p$ - $n$ junction diode, the repulsion of holes and electrons takes place which decreases width of potential barrier by striking the combination of holes and electrons. The width of depletion region in forward biased is less than the reversed biased. Hence, the graph of the potential barrier in the depletion region is given by