Photodiodes

PhotodiodesA photodiode is a semi-conductor diode. Under the influence of optical radiation its photoconductivity is unilateral. A photodiode is a semi-conductor crystal usually with an electron-hole junction (a p-n junction). It has two metal leads and is built-into a protective body made either of metal or plastic. A photodiode can work in two modes. The photoconductive mode means there is a source of DC current in the external circuit. It creates back bias at the p-n junction. The photovoltaic mode means that there is no such source.Like photoresistors, photodiodes are used in certain modes for controlling electric current in a circuit of photodiodes in accordance with the change in the incident radiation intensity. Within wide limits, photocurrent inside a photodiode is in linear proportion to the incident radiation intensity. It almost doesn't depend on the bias voltage. In the photovoltaic mode a photodiode is used like a semi-conductor photocell to generate photo e.m.f.Threshold of sensitivity and level of noise are the two main parameters of a photodiode. The spectral sensitivity range is within 0.3 to 15 micrometers. The lag equals the operating time. An avalanche photodiode is a variety of photodiodes with a p-n structure. The so called avalanche multiplication of current in the p-n junction is used to increase the sensitivity. It is based on the effect of collision atom ionisation caused by photoelectrons in the junction area. The avalanche multiplication factor is 102 to 104 Oe.There are also photodiodes with the p-i-n structure. Their characteristics are close to those of the photodiodes with the p-n structure. However the former have a much smaller lag."Chip and Dip" offers photodiodes of the BPV series manufactured by Vishey as well as domestically produced photodiodes of the FD series. Photodiodes are part of many complex optoelectronic devices. This is why they are widely used in automatic equipment, as well as in laser, digital and measuring technologies.

Category:

Science & Technology

Tags:

• diode
• light
• p-n junction
• photo
• semiconductor device

[acika72]

@CognitiveNetwork silicium!

[CognitiveNetwork]

What type of metal is the protetcive frame, the leads and the part covering the top of the chip made of? Please name, material.