 Dark current (physics)

Dark current is charge produced in a detector without illumination, often by thermally excited carriers. Cooling reduces it, although cooling requirements also depend on the wavelength range and thermal background.

Dark current refers to the small amount of electric current that flows through a photodetector (such as a photodiode or a CCD—charge-coupled device) even when no photons are incident on the device. This current is a result of thermally generated charge carriers and can occur in various types of detectors.