Step 1: Depletion Layer Formation.
A p-n junction consists of p-type (excess holes) and n-type (excess electrons) semiconductors. Due to differing concentrations, electrons move from the n-side to the p-side, and holes move from the p-side to the n-side. Recombination near the junction creates a charge-free zone known as the depletion layer. The p-side becomes negatively charged (due to acceptor ions), and the n-side becomes positively charged (due to donor ions).Step 2: Potential Barrier Formation.
The charge imbalance in the depletion layer generates an electric field directed from the n-side (positive) to the p-side (negative). This field impedes further diffusion of majority carriers, establishing a potential barrier. At equilibrium, this barrier prevents net charge movement. For silicon diodes, this barrier is typically 0.7 V.Step 3: Diagrammatic Representation.
The accompanying diagram depicts a p-n junction with the p-side on the left and the n-side on the right. The depletion layer, a shaded region surrounding the junction, contains negative ions on the p-side and positive ions on the n-side. An arrow illustrates the electric field's direction from n to p, and a potential energy graph demonstrates the barrier's height.Step 4: Rectification Capability.
The junction diode's ability to conduct current in one direction (forward bias: p to n) while blocking it in the opposite direction (reverse bias: n to p) makes it suitable for rectification, converting AC to DC.