Chidule: Kapangidwe koyambira ndi mfundo yogwirira ntchito ya chipangizo chowunikira mafunde (avalanche photodetector)Chowunikira zithunzi cha APD) zimayambitsidwa, njira yosinthira kapangidwe ka chipangizocho imasanthulidwa, momwe kafukufuku wamakono akufotokozedwera mwachidule, ndipo chitukuko chamtsogolo cha APD chikuphunziridwa mtsogolo.
1. Chiyambi
Chowunikira kuwala ndi chipangizo chomwe chimasintha zizindikiro za kuwala kukhala zizindikiro zamagetsi.chowunikira zithunzi cha semiconductor, chonyamulira chopangidwa ndi chithunzi chomwe chimayambitsidwa ndi photon yomwe yachitika chimalowa mu dera lakunja pansi pa mphamvu ya bias yomwe imagwiritsidwa ntchito ndikupanga photocurrent yoyezeka. Ngakhale pa mphamvu yayikulu yoyankha, PIN photodiode imatha kupanga ma electron-hole pair awiri okha, omwe ndi chipangizo chopanda phindu lamkati. Kuti ayankhe bwino, avalanche photodiode (APD) ingagwiritsidwe ntchito. Mphamvu yowonjezera ya APD pa photocurrent imachokera ku ionization collision effect. Pazifukwa zina, ma elekitironi ndi mabowo othamanga amatha kupeza mphamvu zokwanira kuti agundane ndi lattice kuti apange ma electron-hole pair atsopano. Njirayi ndi chain reaction, kotero kuti ma electron-hole pair awiri opangidwa ndi kuwala amatha kupanga ma electron-hole pair ambiri ndikupanga photocurrent yayikulu yachiwiri. Chifukwa chake, APD ili ndi mphamvu yayikulu yoyankha komanso phindu lamkati, zomwe zimathandizira chiŵerengero cha chizindikiro-ku-phokoso cha chipangizocho. APD imagwiritsidwa ntchito makamaka m'makina olumikizirana akutali kapena ang'onoang'ono a fiber optical omwe ali ndi zoletsa zina pa mphamvu yowunikira yolandiridwa. Pakadali pano, akatswiri ambiri a zida zamagetsi ali ndi chiyembekezo chachikulu pa zomwe zingachitike pa APD, ndipo amakhulupirira kuti kafukufuku wa APD ndi wofunikira kuti pakhale mpikisano wapadziko lonse lapansi m'magawo ena ofanana.
2. Kupititsa patsogolo ukadaulo wachowunikira zithunzi cha chipale chofewa(Chowunikira zithunzi cha APD)
2.1 Zipangizo
(1)Si photodetector
Ukadaulo wa zinthu za Si ndi ukadaulo wokhwima womwe umagwiritsidwa ntchito kwambiri m'munda wa ma microelectronics, koma siwoyenera kukonzekera zida zomwe zili mu wavelength range ya 1.31mm ndi 1.55mm zomwe zimavomerezedwa kwambiri m'munda wa kulumikizana kwa kuwala.
(2) Ge
Ngakhale kuti ma spectral response a Ge APD ndi oyenera kutengera kutayika kochepa komanso kufalikira kochepa mu optical fiber transmission, pali zovuta zambiri pakukonzekera. Kuphatikiza apo, chiŵerengero cha electron ndi hole ionization cha Ge chili pafupi ndi () 1, kotero n'kovuta kukonzekera zipangizo za APD zogwira ntchito bwino.
(3)Mu 0.53Ga0.47As/InP
Ndi njira yothandiza kusankha In0.53Ga0.47Monga gawo loyamwa kuwala la APD ndi InP ngati gawo lochulukitsa. Chiwopsezo cha kuyamwa kwa zinthu za In0.53Ga0.47As ndi 1.65mm, kutalika kwa 1.31mm, 1.55mm ndi pafupifupi 104cm-1 high absorption coefficient, chomwe ndi chinthu chomwe chimakondedwa kwambiri pa gawo loyamwa la chowunikira kuwala pakadali pano.
(4)Chowunikira zithunzi cha InGaAs/Muchowunikira zithunzi
Mwa kusankha InGaAsP ngati gawo loyamwa kuwala ndi InP ngati gawo lochulukitsa, APD yokhala ndi kutalika kwa yankho la 1-1.4mm, mphamvu yayikulu ya quantum, mphamvu yamdima yochepa komanso kuchuluka kwa chipale chofewa kumatha kukonzedwa. Mwa kusankha zigawo zosiyanasiyana za alloy, magwiridwe antchito abwino kwambiri a mafunde enaake amapezeka.
(5)InGaAs/InAlAs
Zinthu za In0.52Al0.48As zili ndi mpata wa band (1.47eV) ndipo sizimayamwa pamlingo wa wavelength wa 1.55mm. Pali umboni wakuti In0.52Al0.48As epitaxial layer yopyapyala imatha kupeza mawonekedwe abwino a gain kuposa InP ngati multiplicator layer pansi pa jekeseni yoyera ya ma elekitironi.
(6)InGaAs/InGaAs (P) /InAlAs ndi InGaAs/In (Al) GaAs/InAlAs
Kuchuluka kwa ionization ya zinthu ndi chinthu chofunikira chomwe chimakhudza magwiridwe antchito a APD. Zotsatira zake zikuwonetsa kuti kuchuluka kwa ionization ya collision ya multiplier layer kumatha kukwezedwa poyambitsa InGaAs (P) /InAlAs ndi In (Al) GaAs/InAlAs superlattice structures. Pogwiritsa ntchito kapangidwe ka superlattice, mainjiniya a band amatha kuwongolera mwadala kusagwirizana kwa m'mphepete mwa band pakati pa conduction band ndi valence band values, ndikuwonetsetsa kuti conduction band discontinuity ndi yayikulu kwambiri kuposa valence band discontinuity (ΔEc>>ΔEv). Poyerekeza ndi InGaAs bulk materials, InGaAs/InAlAs quantum well electron ionization rate (a) imawonjezeka kwambiri, ndipo ma elekitironi ndi mabowo amapeza mphamvu yowonjezera. Chifukwa cha ΔEc>>ΔEv, zitha kuyembekezera kuti mphamvu zomwe ma elekitironi amapeza zimawonjezera kuchuluka kwa ionization ya ma elekitironi kuposa momwe mphamvu ya mabowo imathandizira kuchuluka kwa ionization ya mabowo (b). Chiŵerengero (k) cha ionization ya ma elekitironi ku kuchuluka kwa ionization ya mabowo chimawonjezeka. Chifukwa chake, chinthu chowonjezera mphamvu ya bandwidth (GBW) komanso phokoso lochepa zitha kupezeka pogwiritsa ntchito mapangidwe a superlattice. Komabe, kapangidwe ka chitsime cha InGaAs/InAlAs quantum APD, komwe kumatha kuwonjezera mtengo wa k, ndikovuta kugwiritsa ntchito pa optical receivers. Izi zili choncho chifukwa chakuti chinthu chochulukitsa chomwe chimakhudza kuyankha kwakukulu chimachepetsedwa ndi mdima, osati phokoso la kuchulukitsa. Mu kapangidwe kameneka, mdima umayambitsidwa makamaka ndi mphamvu ya tunneling ya InGaAs well layer yokhala ndi band gap yopapatiza, kotero kuyambitsidwa kwa quaternary alloy ya wide-band gap, monga InGaAsP kapena InAlGaAs, m'malo mwa InGaAs ngati chitsime cha quantum well structure kumatha kuletsa mdima.
Nthawi yotumizira: Novembala-13-2023