Concept:Forward bias raises the electrostatic potential of the P-region relative to the N-region, reducing the height of the energy barrier that opposes majority carrier diffusion.
Formula:$$q V_{\text{net}} = e(V_B - V_F)$$
Solution:- At equilibrium, the energy band barrier height is \( e V_B \).
- Applying a forward bias \( V_F \) raises the electron energy levels on the N-side relative to the P-side.
- This reduces the effective energy barrier to \( e(V_B - V_F) \), enabling majority carriers to cross the junction.
Why other options are incorrect:- Option B: Increasing the energy barrier to \( e(V_B + V_F) \) occurs under reverse bias.
- Option C: The fundamental bandgap (\( E_g \)) is an intrinsic property of the crystal and is not eliminated by biasing.
- Option D: Forward bias shifts the N-side bands upward in energy relative to the P-side bands.
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