Briefly describe electron and hole motions in a \(p-n\) junction for forward and reverse biases; then explain how these lead to rectification.

Question: Explain how the majority carrier motion changes in a p-n junction under forward and reverse biases and how it leads to rectification. Answer: In a p-n junction under forward bias, the applied voltage reduces the barrier height, allowing majority carriers (holes from the p-type semiconductor and electrons from the n-type semiconductor) to flow across the junction and recombine, leading to current flow. However, under reverse bias, the applied voltage increases the barrier height, inhibiting the flow of majority carriers across the junction and resulting in little or no current flow. This characteristic of the p-n junction diode, allowing current flow primarily in the forward bias direction and blocking it in reverse bias, results in rectification.