Photoconductivity


Photoconductivity

Photoconductivity is an optical and electrical phenomenon in which a material becomes more conductive due to the absorption of electro-magnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation. Lead content of the surrounding area can be a factor in the effectiveness of this, however. When light is absorbed by a material like a semiconductor, the number of free electrons and holes changes and raises the electrical conductivity of the semiconductor. To cause excitation the light that strikes the semiconductor must have enough energy to raise electrons across the forbidden bandgap or by exciting the impurities within the bandgap. When a bias voltage and a load resistor are used in series with the semiconductor, a voltage drop across the load resistors can be measured when the change in electrical conductivity varies the current flowing through the circuit. Two classic examples of photoconductive materials are the polymer polyvinylcarbazole, which is used extensively in photocopying (xerography); and lead sulfide, used in infrared detection applications, such as the U.S. Sidewinder and Russian Atoll heat-seeking missiles and selenium, as employed in early television and xerography experiments.

See also, photoconductor and photodiode.

Application

solar cell
photoconductive antenna


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  • photoconductivity — /foh toh kon duk tiv i tee/, n. Physics. the increase in the electrical conductivity of a substance, often nonmetallic, caused by the absorption of electromagnetic radiation. [1925 30; PHOTO + CONDUCTIVITY] * * * ▪ physics       the increase in… …   Universalium

  • photoconductivity — fotolaidumas statusas T sritis chemija apibrėžtis Medžiagos elektrinio laidžio padidėjimas paveikus ją šviesa. atitikmenys: angl. photoconductivity rus. фотопроводимость …   Chemijos terminų aiškinamasis žodynas

  • photoconductivity — fotolaidis statusas T sritis fizika atitikmenys: angl. photoconductivity vok. lichtelektrische Leitfähigkeit, f; photoelektrische Leitfähigkeit, f; Photoleitfähigkeit, f rus. фотопроводимость, f pranc. photoconductance, f …   Fizikos terminų žodynas

  • photoconductivity — noun Date: 1929 electrical conductivity that is affected by exposure to electromagnetic radiation (as light) …   New Collegiate Dictionary

  • photoconductivity — noun An increase in the electrical conductivity of a material as a result of incident electromagnetic radiation See Also: photoconduction, photoconductive …   Wiktionary

  • Photoconductivity — Фотопроводимость …   Краткий толковый словарь по полиграфии

  • photoconductivity — pho·to·con·duc·tiv·i·ty .kän .dək tiv ət ē, kən n, pl ties electrical conductivity that is affected by exposure to electromagnetic radiation (as light) …   Medical dictionary

  • photoconductivity — [ˌfəʊtə(ʊ)kɒndʌk tɪvɪti] noun increased electrical conductivity caused by the presence of light. Derivatives photoconductive adjective photoconductor noun …   English new terms dictionary

  • photoconductivity — pho·to·conductivity …   English syllables

  • photoconductivity — pho•to•con•duc•tiv•i•ty [[t]ˌfoʊ toʊˌkɒn dʌkˈtɪv ɪ ti[/t]] n. phs elm the increase in the electrical conductivity of a substance, caused by the absorption of electromagnetic radiation • Etymology: 1925–30 pho to•con•duc′tive kənˈdʌk tɪv adj …   From formal English to slang


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