Concept:In forward bias, the external voltage is applied in opposition to the internal barrier potential (positive terminal to p-type and negative to n-type), which pushes majority carriers toward the junction and counteracts the built-in electric field.
Formula:$$V_{\text{net}} = V_0 - V_f$$
Solution:- The applied forward voltage \(V_f\) opposes the junction's built-in potential barrier \(V_0\).
- This reduces the net electric field across the space-charge layer.
- As majority carriers are forced closer to the junction interface, the depletion region narrows significantly.
Why other options are incorrect:- Option A: Increasing barrier potential and widening of the depletion layer occur in reverse bias.
- Option B: The barrier potential changes as a direct function of the applied external voltage.
- Option D: The barrier is gradually reduced and is overcome only when \(V_f \ge V_0\) (e.g., \(0.7\text{ V}\) for Si).
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