Kev tsim ntawm 270 nm- wavelength sib sib zog nqus ultraviolet-C (UVC) arrays ntawm micro-LEDs rau qhov tsis muaj qhov sib thooj photolithography tau tshaj tawm los ntawm Suav cov kws tshawb fawb [Feng Feng li al, xwm photonics, luam tawm online 15 Lub Kaum Hli 2024].
"UVC micro-LED arrays muaj nuj nqis ntau ntxiv hauv photolithography thiab photochemistry ua cov cuab yeej tsim cov duab tsis zoo thiab hloov lawv mus rau lub teeb- cov ntaub ntawv rhiab heev xws li photoresists, tshem tawm qhov xav tau rau photomasks kim," hais pab pawg los ntawm Suzhou Institute of Nanotech} Southern University of Science, {2 thiab Technology, thiab Hong Kong University of Science thiab Technology.
Nyob rau hauv sib piv rau mercury vapor teeb, UVC LEDs muaj keeb kwm tau tsim feem ntau rau cov kab mob sterilization daim ntawv thov vim rau lawv cov high efficiency, ntev lub neej, thiab tsis muaj ib puag ncig.
Lub flip-chip UVC micro-LED system yog qhia hauv daim duab 1. b. Cov duab ntawm 6μmx6μm UVC micro-LED array raws li pom los ntawm scanning electron microscopy, nrog ib tug 5μmx5μm sawv- ib leeg array suav nrog ua ib qho inset. c. Micrography ntawm standalone li siv electroluminescence (EL).
UVC LED arrays tau tsim los ntawm cov kws tshawb fawb siv kev lag luam 2-inch aluminium gallium nitride (AlGaN) epitaxial wafers (Daim duab 1). "Qhov kev hais lus hneev taw no ua rau muaj teeb meem loj hauv kev ua tiav loj- hom UVC micro-LED cov lus qhia, vim nws ua rau muaj qhov sib txawv ntawm qhov sib txawv thaum lub sij hawm tsim cov txheej txheem xws li electrode patterning, qhov etching, thiab flip-chip bonding," pab neeg sau ntawv, hais txog cov teeb meem 10 ntau dua los ntawm μ
Cov teeb meem cuam tshuam los ntawm qhov tseem ceeb lattice thiab thermal expansion mismatch ntawm sapphire substrate thiab AlGaN txheej yog txuas rau qhov khoov no.
Los ntawm kev ua haujlwm me me wafer feem uas tau singulated ntawm laser dicing, cov kws tshawb fawb tau tuaj yeem txo qhov cuam tshuam ntawm kev khoov thiab ua tiav qhov kev lees paub zoo hauv array patterning mus rau 3μm mesa widths.
Ultrathin npib tsib xee / kub, uas yuav luag pob tshab hauv cheeb tsam UVC wavelength, ua rau sab saum toj p-kev sib cuag.
Hauv qab kev tsis ncaj ncees, cov cuab yeej tshwm sim tau pom cov dej xau tsawg heev, hauv qab cov cuab yeej ntsuas qhov txwv 100fA. Pab neeg no tau sau tseg tias qhov no yog vim qhov atomic layer deposition (ALD)-loj sidewall passivation thiab txo cov phab ntsa puas los ntawm kev kho tetramethylammonium hydroxide (TMAH).
Ntau dua tam sim no ceev rau ib qho kev tsis ncaj ncees tau pom tias muaj txiaj ntsig zoo rau cov khoom siv me me, ua rau muaj kev sib txawv ntau dua tam sim no thoob plaws hauv LED.
"Qhov kev txhim kho saum npoo- rau- ntim piv thiab txo tam sim no- cov nyhuv ntawm cov neeg coob coob pab txhim kho cov cua sov hauv cov khoom siv me me, txo qis thermal degradation nyob rau hauv kev txhaj tshuaj tam sim no," pab pawg tau hais.
Raws li qhov kev tsis ncaj ncees rau pem hauv ntej tau nce los ntawm 3.95V rau 4.2V, cov khoom siv 'zoo tshaj plaws tau txo los ntawm 3.9 txog 2.8. Tsis yog-radiative recombination tshwm sim los ntawm epitaxial wafers 'suboptimal zoo tau txais txiaj ntsig nrog lub hom phiaj siab.
Raws li cov kws tshawb fawb, cov phab ntsa yog qhov tsis tseem ceeb ntawm qhov tsis yog -radiative recombination centres vim yog TMAH thiab kev kho mob uas lawv tau siv. Muaj qee qhov qhia, txawm li cas los xij, tias "kev kho mob passivation thiab TMAH yuav tsis muaj txiaj ntsig zoo hauv kev tawm tsam tsis yog -radiative recombinations los ntawm qhov tsis xws luag los ntawm kev puas tsuaj ntawm phab ntsa" hauv cov khoom siv me me, nqis mus rau 3μm.
Raws li tus ntaus ntawv me me shrinks los ntawm 100μm mus rau 3μm, lub ncov sab nraud quantum efficiency (Daim duab 2) thawb mus rau ntau dua tam sim no ntom, mus ntawm 15A / cm2 mus rau 70A / cm2. Cov EQEs yog qhov kev txiav txim ntawm qhov loj dua qhov uas tuaj yeem tau txais nrog ntsuab lossis xiav passivated LEDs.
Daim duab 2 qhia txog lub ncov EQE thiab EQE droop piv rau txhua lub cuab yeej loj (dots) ua ke nrog cov kab sib piv rau tus nqi ncov.
"Lub EQE poob qis los ntawm 67.5% mus rau 17.9% raws li cov cuab yeej loj zuj zus," pab pawg pom, ua kom pom tias cov khoom siv me me muab kev txhim kho kev ruaj ntseg ntawm lub teeb emission ntawm ntau dua tam sim no vim tias lawv cov cua sov zoo dua.
Ntau dua tam sim no - nthuav dav uniformity thiab txhim kho lub teeb extraction efficiency (LEE) tau txais txiaj ntsig los ntawm cov kws tshawb fawb txog qhov nce hauv EQE rau cov kab uas hla tsawg dua 30 μm. "Cov khoom me me tso tawm lub teeb ze rau ntawm phab ntsa, ua rau muaj kev cuam tshuam ntawm phab ntsa ntau dua thiab ua rau LEE siab dua," cov kws tshawb fawb hais.
Cov khoom siv puv - dav ntawm ib nrab siab tshaj plaws (FWHM) tsawg dua 21 nm, thiab lawv qhov siab tshaj plaws wavelength yog nyob ib ncig ntawm 270 nm. Ntawm qhov tsis tshua muaj tam sim no, 3μm ntaus ntawv lub ncov wavelength blueshifted los ntawm 2 nm, thaum nyob rau ntawm cov dej siab dua (tshaj li 70A / cm2), nws redshifted los ntawm 1 nm.
Raws li cov kws tshawb fawb, qhov kev hloov pauv no yog tshwm sim los ntawm kev sib tw - ua kom cov teebmeem thiab nws tus kheej - cua sov - ntxias bandgap shrinking sib tw nrog ib leeg. Txoj kev txhim kho tshav kub hloov pauv, uas ua rau qeeb qeeb hauv qhov sib txuas ntawm qhov kub thiab txias, yog lub luag haujlwm rau tag nrho cov spectral hloov mus rau txhua qhov tam sim no ntom ntom, uas tsuas yog kwv yees li 2 nm.
Nrog rau qhov ceev ntawm 43.6W / cm2, lub teeb tso zis hluav taws xob (LOP) ntawm 100μm LEDs yog 4.5mW ntawm 35mA. Qhov siab tshaj plaws LOP ceev rau 3μm LEDs yog 396W / cm2. "Qhov no kuj tseem yuav yog vim qhov cuam tshuam ntawm kev cuam tshuam hauv AlGaN ntau- txheej, qhov twg cov khoom siv loj dua tau nce lub zog poob vim txoj kev kho qhov muag ntev dua los ntawm ntau lub qhov dej quantum rau saum huab cua." Pab neeg no sau tseg tias cov khoom siv me me, nrog rau tam sim no zoo dua - sib kis zoo ib yam thiab thermal stability, tuaj yeem ua kom muaj zog dua tam sim no, yog li ua kom muaj zog kho qhov muag ntau dua.
Kev sib tshuam kub heev tshwm sim los ntawm kev ua haujlwm ntawm lub zog siab tshaj plaws ua rau muaj kev laus thiab ua rau thermal deterioration.
3μm ntaus ntawv LOP ceev yog 25.9W / cm2 ntawm 100A / cm2. Qhov no muaj "muaj peev xwm zoo heev li photolithography teeb qhov chaw," raws li cov kws tshawb fawb.
Raws li 6μm li ntawm 10μm suab, cov kws tshawb fawb tau nthuav dav qhov loj ntawm UVC LED arrays los ntawm 16x16 pixels uas tau sau tseg yav dhau los hauv cov ntaub ntawv tshawb fawb txog 160x90 pixels (2540 / inch). Rau kev txhim kho rear-sab lub teeb rho tawm los ntawm cov thinner sapphire substrate, cov arrays tau coated nrog ib tug heev UVC-reflective Al saum nto.
Nrog rau pem hauv ntej kev tsis ncaj ncees ntawm 12V thiab qhov ceev tam sim no ntawm 20A / cm2, lub array ua rau lub zog tso zis hluav taws xob ntawm 16.6mW. Ntawm 8A / cm2, EQE nce siab ntawm 4.1%.
Raws li cov kws tshawb fawb, "Lub UVC micro-LED zaub tshaj li 25mW / cm2 calibration ntawm 365nm mercury teeb siv nyob rau hauv Karl Suss MA-6 daim npog ntsej muag kom tau raws li qhov xav tau ntawm photoresist raug koob tshuaj los ntawm kev muab lub zog kho qhov muag txaus 1.1W-screen txog li 2 cm.
Txhawm rau ntsuas cov peev txheej photolithography, siv 320x140 UVC array nrog 9μm pixels ntawm 12μm qhov sib nrug (Daim duab 3). Indium pob tau siv los tig-chip nplaum cov array mus rau CMOS tsav nti. Lub i- kab rhiab heev AZ MiR 703 nyob rau hauv ib qho kev sib thooj qauv teeb ua hauj lwm raws li qhov kev ntsuam xyuas tus photoresist. Pom tau micro-Piv txwv li, LED zaub, tej zaum yuav raug tsim los siv txoj hauv kev photolithography.
Daim duab 3: UVC micro-LED zaub photolithography qhia tawm qhov profile nto (txoj cai) thiab cov duab tsis muaj daim npog ntsej muag (sab laug) ntawm photoresist-coated wafers. Rau tsib vib nas this, kis tau ntawm 80mA.
Txawm hais tias cov qauv kev daws teeb meem tsis zoo li qhov uas tau txais kev sib cuag, cov kws tshawb fawb tau hais tias tsis muaj daim npog ntsej muag yuav ua kom zoo dua los ntawm cov lens zoo sib xws thiab cov kev tsom mus rau. Xws li daim npog ntsej muag tsis muaj photolithography yuav txuag tau lub semiconductor kev lag luam ib qho tseem ceeb ntawm lub sij hawm thiab nyiaj txiag los ntawm kev ua kom deb li deb raws li qhov yuav tsum tau rau laser -sau lub qhov ncauj qhov ntswg, tshwj xeeb tshaj yog vim hais tias nqaim linewidths mus rau lub pixel loj ntawm micro- tso saib circuits qhia tau hais tias zoo heev.
Los ntawm kev txhim kho qhov zoo ntawm epitaxial wafer thiab ua kom tau raws li qhov tseeb dua, cov kws tshawb fawb xav mus dhau qhov kev txwv tam sim no ntawm 320x140 pixels thiab qhib lub qhov rooj kom siab dua - daws teeb meem UVC micro- LED zaub nrog txog 8K pixels hauv txhua qhov loj me, uas yuav tsum tau ua rau HD thiab U daws teeb meem.
https://www.benweilight.com/lighting-tube-bulb/led-solar-street-light-outdoor.html
