The working principle and main characteristics of photodiodes 2

When reverse biased, the electric fields in the P and N regions form a potential barrier, causing the photodiode to be in a cut-off state with only a very small reverse saturation current. When light shines on the PN junction, the photo generated carriers move under the driving force of the electric field, resulting in a weak reverse current.diode

2. Main characteristics of photodiodes:

(1) Optoelectronic response speed: Photodiodes have a fast response speed and can achieve high-frequency signal reception and transmission. This depends on the generation, diffusion, and collection rates of photo generated charge carriers.diode

(2) Spectral response range: Different types of photodiodes have different response capabilities to light of different wavelengths. Common photodiodes include visible light and infrared light. The wavelength range determines the application field of photodiodes.

(3) Quantum efficiency: Quantum efficiency refers to the efficiency of a photodiode in converting incident light into electrons. It depends on the material and structural design of the photodiode, generally ranging from 10% to 90% in the visible light range.diode

(4) Linearity: The linearity of a photodiode refers to the degree of linear relationship between the input optical signal and the output current. Good linearity can ensure the accuracy and stability of photoelectric conversion.diode