Mtundu wachipangizo chowunikira zithunzikapangidwe
Chowunikira zithunzindi chipangizo chomwe chimasintha chizindikiro cha kuwala kukhala chizindikiro chamagetsi, kapangidwe kake ndi mitundu yake, chingagawidwe m'magulu otsatirawa:
(1) Chowunikira zithunzi chowongolera kuwala
Zipangizo zowongolera kuwala zikakumana ndi kuwala, chonyamulira chopangidwa ndi kuwala chimawonjezera mphamvu ya kuwala ndi kuchepetsa mphamvu ya kuwala. Zonyamulira zomwe zimayatsidwa kutentha kwa chipinda zimasuntha molunjika pansi pa mphamvu ya magetsi, motero zimapanga mphamvu ya kuwala. Pansi pa kuwala, ma elekitironi amasangalala ndipo kusintha kumachitika. Nthawi yomweyo, zimayendayenda pansi pa mphamvu ya magetsi kuti zipange mphamvu ya kuwala. Zonyamulira zomwe zimapangidwa ndi kuwala zimawonjezera mphamvu ya kuwala kwa chipangizocho motero zimachepetsa mphamvu ya kuwala. Zowunikira kuwala kwa kuwala nthawi zambiri zimawonetsa mphamvu ya kuwala kwa kuwala komanso mphamvu ya kuwala, koma sizingayankhe zizindikiro zamagetsi zamagetsi, kotero liwiro la kuyankha ndi lochepa, zomwe zimalepheretsa kugwiritsa ntchito zipangizo zowongolera kuwala m'mbali zina.
(2)Chowunikira zithunzi cha PN
Chowunikira ma PN chimapangidwa ndi kukhudzana pakati pa zinthu za semiconductor za mtundu wa P ndi zinthu za semiconductor za mtundu wa N. Kulumikizana kusanapangidwe, zinthu ziwirizi zimakhala zosiyana. Mlingo wa Fermi mu semiconductor wa mtundu wa P uli pafupi ndi m'mphepete mwa gulu la valence, pomwe mlingo wa Fermi mu semiconductor wa mtundu wa N uli pafupi ndi m'mphepete mwa gulu la conduction. Nthawi yomweyo, mlingo wa Fermi wa zinthu za mtundu wa N m'mphepete mwa gulu la conduction umasunthidwa pansi mpaka mlingo wa Fermi wa zinthu ziwirizi uli pamalo omwewo. Kusintha kwa malo a gulu la conduction ndi gulu la valence kumaphatikizidwanso ndi kupindika kwa gululo. Malo olumikizirana a PN ali mu equilibrium ndipo ali ndi mlingo wofanana wa Fermi. Kuchokera mbali ya kusanthula kwa chonyamulira cha charge, zonyamulira zambiri za charge mu zinthu za mtundu wa P ndi mabowo, pomwe zonyamulira zambiri za charge mu zinthu za mtundu wa N ndi ma electron. Zinthu ziwirizi zikakumana, chifukwa cha kusiyana kwa kuchuluka kwa chonyamulira, ma electron mu zinthu za mtundu wa N adzafalikira ku mtundu wa P, pomwe ma electron mu zinthu za mtundu wa N adzafalikira mosiyana ndi mabowo. Malo osalipidwa omwe amasiyidwa ndi kufalikira kwa ma elekitironi ndi mabowo adzapanga gawo lamagetsi lomangidwa mkati, ndipo gawo lamagetsi lomangidwa mkati lidzayenda motsatira kusuntha kwa chonyamulira, ndipo njira yosunthira ili yosiyana ndi njira yofalikira, zomwe zikutanthauza kuti kupangika kwa gawo lamagetsi lomangidwa mkati kumalepheretsa kufalikira kwa chonyamulira, ndipo pali kufalikira ndi kusuntha mkati mwa PN junction mpaka mitundu iwiri ya mayendedwe italinganizidwa, kotero kuti kuyenda kwa chonyamulira chosasunthika kukhale zero. Kulinganiza kwamkati kwamphamvu.
Pamene malo olumikizirana a PN akumana ndi kuwala, mphamvu ya photon imasamutsidwira ku chonyamulira, ndipo chonyamulira chopangidwa ndi photo, kutanthauza kuti, awiriawiri a ma elekitironi opangidwa ndi photo, amapangidwa. Pansi pa mphamvu ya magetsi, ma elekitironi ndi mabowo amasunthira ku dera la N ndi dera la P motsatana, ndipo kusuntha kwa chonyamulira chopangidwa ndi photo kumapanga photocurrent. Iyi ndiyo mfundo yaikulu ya chonyamulira cha PN junction.
(3)Chowunikira chithunzi cha PIN
Pin photodiode ndi chinthu cha mtundu wa P ndi N pakati pa I layer, I layer ya chinthucho nthawi zambiri imakhala chinthu chamkati kapena chopanda doping. Njira yake yogwirira ntchito ndi yofanana ndi PN junction, pamene PIN junction ikuwonetsedwa ku kuwala, photon imasamutsa mphamvu kupita ku electron, ndikupanga photogenerated charge carriers, ndipo munda wamagetsi wamkati kapena munda wamagetsi wakunja udzalekanitsa ma electron-hole pair opangidwa ndi photo mu depletion layer, ndipo drifted charge carriers amapanga current mu external circuit. Ntchito yomwe layer I imaseweredwa ndi layer I ndikukulitsa m'lifupi mwa depletion layer, ndipo layer I idzakhala depletion layer yonse pansi pa bias voltage yayikulu, ndipo ma electron-hole pair opangidwa adzalekanitsidwa mwachangu, kotero liwiro loyankha la PIN junction photodetector nthawi zambiri limakhala lachangu kuposa la PN junction detector. Ma carriers kunja kwa I layer amasonkhanitsidwanso ndi depletion layer kudzera mu diffusion motion, ndikupanga diffusion current. Makulidwe a I layer nthawi zambiri amakhala ochepa kwambiri, ndipo cholinga chake ndikukweza liwiro loyankha la depletion.
(4)Chowunikira zithunzi cha APDchiphalaphala cha phiri la photodiode
Njira yachiphalaphala cha phiri la photodiodeChimafanana ndi cha PN junction. APD photodetector imagwiritsa ntchito PN junction yochuluka kwambiri, mphamvu yogwirira ntchito yochokera pa kuzindikira kwa APD ndi yayikulu, ndipo pamene reverse bias yayikulu yowonjezeredwa, ionization ya collision ndi avalanche multiplication zimachitika mkati mwa APD, ndipo magwiridwe antchito a detector amawonjezeka photocurrent. APD ikalowa mu reverse bias mode, mphamvu yamagetsi mu depletion layer idzakhala yamphamvu kwambiri, ndipo zonyamulira zopangidwa ndi photogenerated zopangidwa ndi kuwala zidzalekanitsidwa mwachangu ndikusunthika mwachangu pansi pa mphamvu ya magetsi. Pali kuthekera kuti ma elekitironi adzagundana mu lattice panthawiyi, zomwe zimapangitsa kuti ma elekitironi mu lattice asinthidwe kukhala ionized. Njirayi imabwerezedwanso, ndipo ma ion ionized mu lattice amagundananso ndi lattice, zomwe zimapangitsa kuti chiwerengero cha zonyamulira mphamvu mu APD chiwonjezeke, zomwe zimapangitsa kuti mphamvu yamagetsi ikhale yayikulu. Ndi njira yapaderayi mkati mwa APD yomwe ma detector okhala ndi APD nthawi zambiri amakhala ndi mawonekedwe a liwiro loyankha mwachangu, phindu lamphamvu lamagetsi komanso kukhudzidwa kwakukulu. Poyerekeza ndi PN junction ndi PIN junction, APD ili ndi liwiro loyankha mwachangu, lomwe ndi liwiro loyankha mwachangu kwambiri pakati pa machubu omwe ali ndi kuwala kwa dzuwa.
(5) Chowunikira zithunzi cha Schottky junction
Kapangidwe koyambira ka Schottky junction photodetector ndi Schottky diode, yomwe makhalidwe ake amagetsi ali ofanana ndi a PN junction yomwe yafotokozedwa pamwambapa, ndipo imakhala ndi unidirectional conductivity yokhala ndi positive conduction ndi reverse cut-off. Pamene chitsulo chokhala ndi high work function ndi semiconductor yokhala ndi low work function zimapanga contact, Schottky barrier imapangidwa, ndipo junction yomwe imachokera imakhala Schottky junction. Njira yayikulu imafanana pang'ono ndi PN junction, potengera N-type semiconductors mwachitsanzo, pamene zinthu ziwiri zimapanga contact, chifukwa cha kusiyana kwa ma electron a zinthu ziwirizi, ma electron omwe ali mu semiconductor amafalikira kumbali yachitsulo. Ma electron ofalikira amasonkhana mosalekeza kumapeto kwa chitsulo, motero amawononga mphamvu yoyambirira yamagetsi yachitsulo, ndikupanga munda wamagetsi womangidwa kuchokera ku semiconductor kupita ku chitsulo pamwamba pa contact, ndipo ma electron adzayenda pansi pa mphamvu ya munda wamagetsi wamkati, ndipo kufalikira ndi kuyenda kwa chonyamulira kudzachitika nthawi imodzi, patatha nthawi kuti afike pa dynamic equilibrium, ndipo potsiriza amapanga Schottky junction. Pansi pa kuwala, dera lotchinga limayamwa kuwala mwachindunji ndikupanga ma electron-hole pairs, pomwe zonyamulira zopangidwa ndi photogenerated mkati mwa PN junction ziyenera kudutsa m'dera lofalikira kuti zikafike m'dera lolumikizirana. Poyerekeza ndi PN junction, photodetector yochokera ku Schottky junction ili ndi liwiro loyankha mwachangu, ndipo liwiro loyankha limatha kufika pamlingo wa ns.
Nthawi yotumizira: Ogasiti-13-2024