The photocurrent is the electric current through a photosensitive device, such as a photodiode, as the result of exposure to radiant power.
The photocurrent may occur as a result of the photoelectric, photoemissive, or photovoltaic effect.
The photocurrent may be enhanced by internal gain caused by interaction among ions and photons under the influence of applied fields, such as occurs in an avalanche photodiode (APD).
As a characterization technique, photocurrent is commonly used to study charge properties such as excitons of semiconductor nanostructures and other light-absorbing materials
When suitable radiation is used, the photoelectric current