d
During the formation of a junction diode, holes from \(p-\) region diffuse into \(n-\) region and electrons from \(n-\) region diffuse into pregion. In both cases, when an electrons meets a hole, they cancel the effect at each other and as a result, a thin layer at the junction becomes free from any of charges carriers. This is called depletion layer. There is a potential gradient in the depletion layer, negative on the \(p-\) side, and positive on the \(n-\) side. The potential difference thus developed across the junction is called potential barrier