Concept:Forward bias applies an external electric field that opposes the built-in barrier field, lowering the potential barrier and allowing majority carriers to narrow the depletion layer.
Formula:$$V_{\text{net}} = V_0 - V_F \quad \text{and} \quad W_{\text{forward}} = \sqrt{\frac{2\epsilon_s (V_0 - V_F)}{q}\left(\frac{1}{N_A} + \frac{1}{N_D}\right)}$$
Solution:- The applied forward voltage \( V_F \) reduces the net potential difference across the junction to \( V_0 - V_F \).
- This allows majority carriers to push closer to the junction, reducing the width of the depletion layer.
Why other options are incorrect:- Option A: The barrier height and depletion width increase under reverse bias, not forward bias.
- Option C: Barrier height and depletion width change together in the same direction.
- Option D: External biasing directly alters the junction electric field and dimensions.
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