Concept:Forward biasing lowers the junction barrier, enabling vast populations of majority carriers from both sides to diffuse across the junction.
Formula:$$I_F = I_0 \left( e^{\frac{qV}{\eta k_B T}} - 1 \right)$$
Solution:- The external forward voltage pushes majority electrons from the N-side and majority holes from the P-side across the narrowed depletion region.
- This produces a substantial, exponentially rising forward diffusion current.
Why other options are incorrect:- Option A: Thermally generated minority carriers account for reverse saturation current, not forward current.
- Option B: Surface leakage is a minor non-ideal parasitic effect observed under reverse bias.
- Option C: Displacement current occurs under rapid AC high-frequency switching, not standard DC conduction.
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