Mfundo yowala ya LED

Zonsenyali yogwirira ntchito yobwezeretsanso mphamvu, nyali yonyamulika yopita kumsasandinyali yamutu yogwira ntchito zambiriGwiritsani ntchito mtundu wa babu la LED. Kuti mumvetse mfundo ya diode led, choyamba muyenera kumvetsetsa chidziwitso choyambira cha ma semiconductor. Kapangidwe ka zinthu za semiconductor ndi pakati pa ma conductor ndi ma insulators. Zinthu zake zapadera ndi izi: pamene semiconductor ikukhudzidwa ndi kuwala kwakunja ndi kutentha, mphamvu yake yoyendetsa magetsi imasintha kwambiri; Kuwonjezera zinyalala zochepa ku semiconductor yoyera kumawonjezera kwambiri mphamvu yake yoyendetsa magetsi. Silicon (Si) ndi germanium (Ge) ndi ma semiconductor omwe amagwiritsidwa ntchito kwambiri mu zamagetsi amakono, ndipo ma elekitironi awo akunja ndi anayi. Pamene ma atomu a silicon kapena germanium amapanga kristalo, ma atomu oyandikana nawo amalumikizana, kotero kuti ma elekitironi akunja agawika ndi ma atomu awiriwa, omwe amapanga kapangidwe ka covalent bond mu kristalo, komwe ndi kapangidwe ka molekyulu kopanda mphamvu zambiri. Pa kutentha kwa chipinda (300K), kutentha kumapangitsa ma elekitironi ena akunja kukhala ndi mphamvu zokwanira kuti achoke ku covalent bond ndikukhala ma elekitironi aulere, njirayi imatchedwa intrinsic excitation. Pambuyo electron itatsegulidwa kuti ikhale free electron, malo otsala amasiyidwa mu covalent bond. Malo otsalawa amatchedwa dzenje. Kuoneka kwa dzenje ndi chinthu chofunikira chomwe chimasiyanitsa semiconductor ndi kondakitala.

Pamene kuchuluka kochepa kwa pentavalent discharge monga phosphorous kwawonjezedwa ku intrinsic semiconductor, kumakhala ndi electron yowonjezera pambuyo popanga covalent bond ndi ma atomu ena a semiconductor. Electron yowonjezera iyi imangofunika mphamvu yochepa kwambiri kuti ichotse bond ndikukhala free electron. Mtundu uwu wa deficial semiconductor umatchedwa electronic semiconductor (N-type semiconductor). Komabe, kuwonjezera pang'ono trivalent elemental disadvalent (monga boron, ndi zina zotero) ku intrinsic semiconductor, chifukwa ili ndi ma elekitironi atatu okha mu layer yakunja, pambuyo popanga covalent bond ndi ma atomu a semiconductor ozungulira, imapanga malo opanda kanthu mu kristalo. Mtundu uwu wa deficial semiconductor umatchedwa hole semiconductor (P-type semiconductor). Pamene N-type ndi P-type semiconductors ziphatikizidwa, pali kusiyana kwa kuchuluka kwa ma free electron ndi mabowo pamalo awo olumikizirana. Ma elekitironi ndi mabowo onse amafalikira kupita ku concentration yotsika, kusiya ma ion omwe ali ndi mphamvu koma osayenda omwe amawononga kusalowerera kwamagetsi koyambirira kwa madera a N-type ndi P-type. Tinthu tomwe timayendetsedwa ndi mphamvu imeneyi nthawi zambiri timatchedwa kuti space charges, ndipo timayikidwa pafupi ndi malo olumikizirana a madera a N ndi P kuti tipange dera lochepa kwambiri la space charge, lomwe limadziwika kuti PN junction.

Pamene magetsi oyendetsera magetsi (forward bias voltage) agwiritsidwa ntchito kumapeto onse a PN junction (voteji yabwino mbali imodzi ya mtundu wa P), mabowo ndi ma free electron amayendayenda, zomwe zimapangitsa kuti magetsi amkati akhale amphamvu. Mabowo atsopano omwe amalowetsedwa amalumikizananso ndi ma free electron, nthawi zina amatulutsa mphamvu yochulukirapo mu mawonekedwe a photons, omwe ndi kuwala komwe timawona komwe kumatulutsidwa ndi ma LED. Mtundu woterewu ndi wopapatiza, ndipo popeza chinthu chilichonse chili ndi band gap yosiyana, kutalika kwa ma photons omwe amatulutsidwa ndi kosiyana, kotero mitundu ya ma LED imatsimikiziridwa ndi zipangizo zoyambira zomwe zimagwiritsidwa ntchito.