A photodiode is a transducer that captures light energy and converts it into electrical energy. Flow is generated when photons are absorbed in the photodiode. A small amount of current is also produced without light.
The photodiode can contain optical filters, integrated lenses, and large or small areas. A photodiode conducts an electric current directly proportional to the amount of light falling on it. This is a perfect direct relationship.
Working principle of Photodiode
The operating principle of a photodiode is that, when many photons of energy attack the diode, it creates several holes for electrons. This mechanism is also called the photoelectric effect inside. If the absorption appears at the intersection of the depletion zone, the carrier is removed from the intersection by the integrated electric field of the depletion zone.
As a result, the hole in the region moves to the anode and the electrons move to the cathode and the flow of photos will be generated. The entire current flowing through the diode is the sum of the absence of light and electric current. So that there is no current needs to be reduced to maximize the sensitivity of the device.