photodiode

electronics

Also known as: photo diode

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July 2, 2026

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A photodiode is a semiconductor device that detects and measures radiant energy, such as light. It operates based on the photoelectric effect, where photons striking the semiconductor material excite electrons, generating an electrical current or voltage.12

Semiconductors, like silicon, have electrical conductivities between those of insulators and conductors. When light with sufficient energy hits a semiconductor, it can free electrons, allowing them to move and conduct electricity. This property makes photodiodes useful in various applications, including light detection in fiber optics, solar cells, and imaging technologies. They can convert light into electrical energy and respond very quickly to changes in illumination.3452

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radiation measurement
Conversion of light to charge
…solid-state device known as a photodiode. A device of this type consists of a thin semiconductor wafer that converts the incident light photons into electron-hole pairs. As many as 80 or 90 percent of the light photons will undergo this process, and so the equivalent quantum efficiency is considerably higher…
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…solid-state device known as a photodiode. A device of this type consists of a thin semiconductor wafer that converts the incident light photons into electron-hole pairs. As many as 80 or 90 percent of the light photons will undergo this process, and so the equivalent quantum efficiency is considerably higher…
Read More

photoelectric effect
Applications
One basic device is the photoelectric cell, or photodiode. Originally, this was a phototube, a vacuum tube containing a cathode made of a metal with a small work function so that electrons would be easily emitted. The current released by the plate would be gathered by an anode held at…
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One basic device is the photoelectric cell, or photodiode. Originally, this was a phototube, a vacuum tube containing a cathode made of a metal with a small work function so that electrons would be easily emitted. The current released by the plate would be gathered by an anode held at…
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radiation measurement
Scintillators
…in a photomultiplier tube or photodiode.
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…in a photomultiplier tube or photodiode.
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spectroscopy
Optical detectors
A photoemissive diode consists of a surface (photocathode) appropriately treated to permit the ejection of electrons by low-energy photons and a separate electrode (the anode) on which electrons are collected, both sealed within an evacuated glass envelope. A photomultiplier tube has a
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A photoemissive diode consists of a surface (photocathode) appropriately treated to permit the ejection of electrons by low-energy photons and a separate electrode (the anode) on which electrons are collected, both sealed within an evacuated glass envelope. A photomultiplier tube has a
Read More