1. Depletion region : The region consisting of immobile positive charge at n-side and immobile negative charge at p-side near the junction acts like a barrier and prevents the further flow of free electrons and holes.
2. Barrier voltage : The negative charge formed at the p-side of the p-n junction is called negative barrier voltage while the positive charge formed at the n-side of the p-n junction is called positive barrier voltage. The total charge formed at the p-n junction is called barrier voltage, barrier potential or junction barrier.