With what considerations in view, a photodiode is fabricated? State its working with the help of a suitable diagram.
Eventhough the current in the forward bias is . known to be more than in the reverse bias, yet the photodiode works in reverse bias. What ;s the reason?
The photodiode is a special purpose silicon diode. It is fabricated with a transparent window to expose its junction to light radiations. It always works on the reverse bias condition below the breakdown voltage.
When visible light of energy enters its depletion region, the electron-hole pairs are generated. These charge carriers are separated by the junction’s electric field and are made to flow across the junction and causes reverse saturation current. The value of the reverse saturation current depends on the intensity of incident radiation and is independent of reverse bias.