Briefly explain how the diffusion and drift currents contribute to the formation of potential barrier in a p-n junction diode

General
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briefly explain how the diffusion and drift currents contribute to the formation of potential barrier in a p-n junction diode.

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Briefly explain how the diffusion and drift currents contribute to the formation of potential barrier in a p-n junction diode

Answer:

In a p-n junction diode, the diffusion and drift currents play crucial roles in the formation of the potential barrier. Here’s how they contribute:

  1. Diffusion Currents:

    • Diffusion currents occur due to the movement of majority charge carriers (electrons in the n-region and holes in the p-region) towards the region of minority carriers.
    • In a p-n junction, electrons diffuse from the n-region to the p-region, and holes diffuse from the p-region to the n-region.
    • This diffusion creates a region near the junction where free charge carriers are depleted, leading to the formation of a depletion region.

  2. Drift Currents:

    • Drift currents result from the application of an external voltage across the p-n junction.
    • When a forward bias voltage is applied, the electrons in the n-region are pushed towards the junction and combine with the holes moving in the opposite direction. This movement constitutes the drift current.
    • Conversely, under reverse bias, the electrons and holes are pulled away from the junction, opposing the flow of current. This flow of charges also contributes to the formation of the potential barrier.

The combination of these diffusion and drift currents leads to the establishment of a potential barrier at the junction of the p-n diode. This barrier prevents further flow of majority carriers across the junction unless an external voltage is applied, enabling the diode to regulate the flow of current efficiently.