When forward bias is applied to a p-n junction, then what happens to the potential barrier…

When forward bias is applied to a p-n junction, then what happens to the potential barrier $\left(\mathrm{V}_{\mathrm{B}}\right)$ and the width $(\mathrm{X})$ of the depletion region?
  1. $V_B$ increase, $X$ decreases
  2. $\mathrm{V}_{\mathrm{B}}$ decreases, $\mathrm{X}$ increase
  3. $\mathrm{V}_{\mathrm{B}}$ increase, $\mathrm{X}$ increase
  4. $\quad V_B$ decreases, $\mathrm{X}$ decreases

Solution

The forward bias voltage opposes the potential barrier. Due to this, the potential barrier is reduced and hence the depletion layer becomes thin. The conduction across p-n junction takes place due to migration of majority carriers from one region to another. Hence, in forward biasing both VB and x decreases.

Asked in: MHT CET 2023 (12 May Shift 1)

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