The working principle and main characteristics of photodiodes 1

A photodiode is a semiconductor device that can convert optical signals into electrical signals. It converts incident light energy into electrical energy through the DCP010512BP photoelectric conversion effect, thereby generating current. Photodiodes are widely used in fields such as photodetection, communication, and optoelectronic measurement. The following will provide a detailed introduction to the working principle and main characteristics of photodiodes.diode

1. Working principle of photodiode:

The photodiode adopts a PN junction, and its working principle is mainly based on built-in electric field and photoelectric effect.

The photoelectric effect refers to the transfer of energy to matter when photons interact with it, causing electrons to transition from the valence band to the conduction band, forming a photo generated carrier. When the photon energy is greater than or equal to the bandgap energy of the material, the generation of photo generated charge carriers will significantly increase.diode

In the PN junction, the P region is enriched with impurities, while the N region is doped with impurities. When forward bias and reverse bias are applied on both sides of the PN junction, i.e. Vd>0 and Vd<0, the photodiode can operate.diode

When forward biased, due to the presence of more charge carriers in the P region, the photodiode will enter a conducting state with a large reverse current. When light shines on the PN junction, the number of photo generated carriers increases, leading to an increase in current.diode