Photoleitend

Photoleitend is a German term that translates to photoconductive in English. Photoconductivity is the increase in electrical conductivity of a material when it is exposed to electromagnetic radiation, such as light. This phenomenon occurs because the incident photons provide energy to electrons, exciting them from a bound state to a mobile state, thereby increasing the number of charge carriers available for conduction.

The effect is typically observed in semiconductor materials. When light with sufficient energy (greater than or equal to the band gap energy of the material) strikes a photoconductor, it can promote electrons from the valence band to the conduction band. This process creates electron-hole pairs, both of which can contribute to electrical current. The greater the intensity of the incident light, the more electron-hole pairs are generated, and thus the higher the conductivity of the material.

Photoconductive materials are used in a variety of applications. One common use is in light sensors, such as those found in automatic streetlights or cameras. They are also employed in photocopiers and laser printers, where they play a crucial role in the electrophotographic process. Photodetectors, which convert light signals into electrical signals, often utilize photoconductive principles. The sensitivity and spectral response of a photoconductor can be tailored by choosing specific materials and doping them appropriately.