Which of the following statements are correct?(A) In a p-n junction d…

The correct answer is Option (3) → (A) and (B) only

At a p-n junction, diffusion leaves uncovered positive donor ions on the n-side and negative acceptor ions on the p-side. This depletion layer has a field from n to p, which sets up the barrier potential.

(A) In a p-n junction diode, accumulation of electric charge of the opposite type on two sides of the junction produces an electric field and a potential barrier — Correct. The opposite ionic charges on the two sides produce the field and the barrier potential.

(B) The potential barrier opposes the movement of the majority charge carriers across the junction. — Correct. The field pushes holes back to the p-side and electrons back to the n-side, so it opposes the diffusion of majority carriers.

(C) In the reverse biased p-n junction, the width of the depletion layer decreases. — Incorrect. In reverse bias the applied voltage adds to the barrier, so the barrier rises and the depletion layer widens.

(D) In forward bias of a p-n junction, the potential barrier increases. — Incorrect. In forward bias the applied voltage opposes the barrier, so the effective barrier becomes \( V_0 - V \), which is smaller.

NCERT (2026-27):
p-n Junction Formation – “… The loss of electrons from the n-region and the gain of electron by the p-region causes a difference of potential across the junction of the two regions. The polarity of this potential is such as to oppose further flow of carriers so that a condition of equilibrium exists.”

p-n Junction Diode Under Forward Bias – “… As a result, the depletion layer width decreases and the barrier height is reduced [Fig. 14.13(b)].”

p-n Junction Diode Under Reverse Bias – “… As a result, the barrier height increases and the depletion region widens due to the change in the electric field.”