Question

The current that exists in the circuit of a photodiode even when no visible light is made incident on it is called

Answer 1

Dark current:

1. Dark current is a kind of leakage current of a photodiode in the reverse direction when it is exposed to light.
2. This type of diode is designed to generate a current which is proportional to the light incident on it.
3. The charge generation rate is due to specific crystallographic defects within the depletion region.
4. Germanium photodiodes have the largest dark currents.
5. Germanium photodiodes provide very narrow band gaps as compared to other semiconductor materials.
6. This is the main disadvantage of the use of germanium photodiodes at small wavelengths and thus they have a large dark current.

Thus, the current which exists in the circuit of a photodiode when no visible light is made incident on it is called dark current.