Concept:Under reverse bias, the electric field at the junction sweeps thermally generated minority carriers across the depletion layer. Because the minority carrier concentration depends almost entirely on temperature and intrinsic thermal generation, the reverse saturation current is largely independent of applied voltage (until breakdown).
Formula:$$I_s \propto T^3 e^{-\frac{E_g}{k_B T}}$$
Solution:- Reverse current is caused by minority electrons in the p-side and minority holes in the n-side.
- These minority carriers are produced by thermal breaking of covalent bonds.
- Consequently, this reverse current depends strongly on temperature rather than the applied reverse voltage.
Why other options are incorrect:- Option A: Majority carriers are blocked by the heightened potential barrier in reverse bias.
- Option C: Connecting wire geometry has negligible influence on junction leakage current.
- Option D: Once reverse saturation is reached, increasing the reverse voltage does not noticeably increase current until breakdown.
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