{"id":2347,"date":"2022-01-02T18:38:30","date_gmt":"2022-01-02T18:38:30","guid":{"rendered":"https:\/\/physics.educour.in\/isc\/?p=2347"},"modified":"2022-01-13T04:23:39","modified_gmt":"2022-01-13T04:23:39","slug":"light-emitting-diode-led","status":"publish","type":"post","link":"https:\/\/physics.educour.in\/isc-physics\/light-emitting-diode-led\/","title":{"rendered":"Light emitting diode (LED)"},"content":{"rendered":"\t\t
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Light Emitting Diode or LED, is a heavily doped p-n junction which under forward bias emits spontaneous radiation. The diode is put inside a transparent cover so that emitted light can come out.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Working of LED:<\/strong> <\/span><\/h3>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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When the diode is forward biased, electrons are sent from n \u2192p (where they are minority carriers) and holes are sent from p \u2192 n (where they are minority carriers). At the junction boundary the concentration of minority carriers increases compared to the equilibrium concentration (i.e., when there is no bias).<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Thus at the junction boundary on either side of the junction, excess minority carriers are there which recombine with majority carriers near the junction. On recombination, the energy is released in the form of photons. Photons with energy equal to or slightly less than the band gap are emitted (i.e. h<\/em>\u03bd \u2264 Eg). <\/em>\u00a0When the forward current of the diode is small, the intensity of light emitted is small. As the forward current increases, intensity of light increases and reaches a maximum.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t

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\"\"<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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