Kev tsim ntawm xiav LED (lub teeb emitting diode), uas tau txiav txim siab nyuaj ua tiav tau ntau xyoo, tau yug los rau kev txuag hluav taws xob thiab teeb pom kev zoo nyob ntev thiab nthuav qhia, uas tau hloov pauv lub ntiaj teb. Ib ntawm qhov kev tshawb fawb tshiab tshaj plaws yog tias nws tuaj yeem tsim UV LEDs nrog lub nthwv dej luv dua li LED xiav.
Ntawm cov duab hluav taws xob ultraviolet, cov duab hluav taws xob sib sib zog nqus tshwj xeeb nrog lub nthwv dej luv luv tshwj xeeb muaj peev xwm ua kom tsis muaj menyuam thiab xav tias yuav siv rau hauv cov chaw tsim khoom thiab cov chaw ua kom dej huv (Daim duab 1). Feem ntau ntawm cov roj teeb tua kab mob tam sim no siv cov tshuaj mercury, tab sis nrog kev nkag mus rau hauv Minamata Treaty ntawm Mercury xyoo 2017, cov zej zog thoob ntiaj teb tau pib ua haujlwm txhawm rau txo kev siv cov mercury. Hauv qhov xwm txheej no, xav kom tob tob ultraviolet UVC LEDs. Cov khoom siv sib sib zog nqus-ultraviolet LEDs tau pib mus rau hauv kev ua lag luam, tab sis tam sim no kev ua kom pom kev zoo thiab lub zog tso tawm tsis txaus.
Hirayama, uas pib tshawb fawb UV LEDs hauv xyoo 1996, tau hais nrog kev ntseeg siab: "Txawm hais tias kev sib tw kev txhim kho tau hnyav heev, tob tob UV UVC LED peb tsim tau ua tiav lub ntiaj teb kev ua haujlwm siab tshaj plaws ntawm 20.3%. Txawm li cas los xij, yog tias peb xav ua kom siv tau thoob plaws, kev ua kom pom kev zoo yuav yog Nws yuav tsum tau txhim kho ntxiv kom dhau qhov qis-siab mercury teeb siv los ua lub teeb tua kab, thiab lub hom phiaj tam sim no yog tshaj 30%."
Cov txheej txheem yooj yim ntawm LED yog pn kev sib tshuam tsim los ntawm kev koom nrog n-hom semiconductor nrog ntau lub tshuab hluav taws xob thiab p-hom semiconductor nrog cov tsis muaj hluav taws xob txaus (nrog qhov). Tom qab siv qhov hluav taws xob, hluav taws xob thiab qhov sib txuas ua ke kom tso lub teeb tawm, tab sis cov xim (nthwv dej) ntawm lub teeb thiab qhov hluav taws xob xav tau kom tso tawm lub teeb sib txawv nyob ntawm seb hom semiconductor. Txhawm rau txhawm rau txhim kho cov khoom siv hluav taws xob uas tuaj yeem tsim lub teeb ntawm qhov xav tau ntev, ntau tus kws tshawb fawb tau tshawb nrhiav ntau yam ntaub ntawv. Hirayama tau hais tias:" Yog tias nws tsuas tuaj yeem tso lub teeb nyob hauv cheeb tsam ultraviolet, nws tsis yog qhov ua tau. Vim tias nws tseem yuav tsum tau tso lub teeb kom muaj txiaj ntsig ntau dua li cov teeb pom kev yav dhau los, thiab tuaj yeem tsim tawm ntau ntawm tus nqi qis." Aluminium gallium nitride (AlGaN) tau cia siab tias yog cov khoom siv tau zoo, tab sis muaj ntau qhov teeb meem.
Lub thev naus laus zis tshiab uas tuaj yeem tsim cov nplais zoo, LEDs tsim pn kev sib txuas los ntawm kev loj hlob muaju nrog cov atoms ntawm cov khoom siv yooj yim (substrate). Cov khoom siv hluav taws xob siv hluav taws xob pheej yig sapphire (Al2O3), tab sis vim qhov sib txawv ntawm qhov nrug (lattice tsis tu ncua) nruab nrab ntawm cov atoms uas ua rau siv lead ua, AlGaN siv lead ua yog deformed thaum nws loj hlob, ua rau muaj qhov tsis xws luag hu ua lattice defects. Cov kab nrib pleb uas nthuav dav raws txoj kab tsis xws luag hu ua qhov tsis xws luag. Yog tias qhov tsis xws luag (kev sib hloov ntawm qhov ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom)) nce, qhov ua kom pom kev zoo dua qub.
Cov LED xiav yuav tsum tsim cov gallium nitride (GaN) siv lead ua zaj duab xis nrog tsawg dua qhov tsis xws luag ntawm cov substrate. Lub thev naus laus zis kom paub zaj duab xis no tau tsim los ntawm Nobel Prize-winning xibfwb ntawm Meijo University, Isamu Akasaki. Rau qhov tob tob ultraviolet LEDs, ib qho txhuas nitride (AlN) siv lead ua zaj duab xis tau tsim ntawm cov substrate thiab AlGaN siv lead ua tau cog rau nws. Tsim kom muaj cov yeeb yaj kiab zoo AlN ntawm cov khoom siv los txo qhov tsis xws luag. Nws rov hais dua:" Txoj kev no tau ua tiav hauv kev txhim kho kev ua kom pom kev zoo, dhau ntawm cov neeg sib tw' pab pawg Asmeskas tshawb fawb."
AlN muaju yog tsim los ntawm cov hlau organic tshuaj vapor tso (MOCVD). Cov khoom siv roj av tau muab xa mus rau lub pob zeb sapphire ntawm qhov kub siab txog 1400 degrees kom nws loj tuaj raws li cov siv lead ua. Txoj hauv kev tsim los ntawm Hirayama thawj zaug loj hlob AlN nitride ua lub hauv paus ntawm lub hauv paus, thiab tshuab cov pa roj ammonia hauv lub plawv kom ua rau nws loj hlob ib sab kom puv qhov sib txawv ntawm cov tub ntxhais. Tom qab ntawd cov pa tau txuas ntxiv txuas mus rau lawv cov kab ntsug. Los ntawm rov ua cov txheej txheem kev txhim kho siv lead ua no, txheej txheej AlN zoo uas tsis muaj qhov tawg tuaj yeem tsim tau (Daim duab 2). Hais tias:" Txhawm rau ua kom muaju zoo, koj yuav tsum ua tib zoo tswj cov pa roj ntau ntau, cov dej ntws thiab cov tshuaj tiv thaiv kub, thiab lwm yam. Cov pa ntws tau yooj yim kom muaj kev kub ntxhov thiab xav tau kev paub ntau yam. Yog li ntawd, cov cuab yeej siv tau yog ib tus kheej tau tsim thiab hloov kho raws li xav tau." .
Txhim kho lub teeb pom kev zoo los ntawm kev ua haujlwm ntawm tus qauv
Lub teeb pom kev zoo cuam tshuam nrog 3 yam. Thawj yog" kev ua haujlwm sab hauv quantum", qhov thib ob yog&"; kev siv hluav taws xob txhaj tshuaj &"; ;. Hirayama ua haujlwm hnyav los txhim kho peb qhov kev ua tau zoo no.
Kev ua haujlwm sab hauv quantum yog tus nqi qhia qhov sib piv ntawm cov tshuab hluav taws xob thiab cov qhov sib txuas uas tsim los ntawm tam sim no kom tso tawm lub teeb, thiab qhia txog qib uas lub teeb ci ntsa iab tso tawm lub teeb zoo. Los ntawm kev ua kom siv lead ua kom zoo thiab txo qhov tsis xws, kev ua haujlwm sab hauv quantum tau ua tiav zoo dua.
Kev siv hluav taws xob txhaj tshuaj yog hais txog kev faib ua feem ntawm cov hluav taws xob uas nkag mus rau txheej txheej ci ci hauv qhov txhaj tshuaj tam sim no. Qhov sib sib zog nqus ultraviolet UV LED muaj teeb meem uas cov tshuaj electron tsis nkag mus rau hauv lub teeb ci ntsa iab, tab sis xau los ntawm p-txheej sab.
Cov lus taw qhia tau hais tias:" Qhov laj thawj yog tias tus naj npawb ntawm qhov hauv p-hom semiconductor tsis sib luag nrog cov lej ntawm cov hluav taws xob hauv n-hom semiconductor. Vim tias nws nyuaj rau nce tus naj npawb ntawm qhov, txheej txheej thaiv hluav taws xob (txheej txheem ntau-quantum teeb meem) tau tsim los txhawm rau cuam tshuam cov hluav taws xob uas tsis muaj qhov txwv uas hla ncaj qha. , Ua tau zoo ua ke" (Daim duab 3). Vim li ntawd, kev txhaj tshuaj hauv tshuab hluav taws xob tau zoo heev.
Npau suav yog siv rau lub teeb ci laser
Qhov tob tob ultraviolet UV LED tsim los ntawm AlGaN kuj muaj qhov zoo hauv daim ntawv thov ntau yam. Nws hais txog kev cia siab:" Los ntawm kev hloov pauv qhov muaj pes tsawg leeg ntawm cov siv lead ua, lub nthwv dej ntawm tob ultraviolet tuaj yeem hloov kho. Qhov no kuj yog tus yam ntxwv. Tam sim no, sib sib zog nqus ultraviolet UVC LEDs tau ua tiav hauv 222-351 nm band. Koj tuaj yeem tsim cov yoj yoj yoj raws li daim ntawv thov. Sib sib zog nqus ultraviolet teeb, xws li lub teeb txog li 310 nanometers siv los kho atopic dermatitis thiab psoriasis, thiab lwm yam."
Nov yog thev naus laus zis hauv kev txhim kho. Lub zog tso tawm yuav tsum tau nce ntxiv los ntawm kaum tawm milliwatts tam sim no mus rau ob peb watts. Nws yuav tsum tau siv los ua kom tsis muaj menyuam, ua kom dej huv, ua kom huab cua huv, kho mob, kev lag luam biochemical, tawv tawv thiab ua tiav, thiab luam ntawv yav tom ntej. Thiab pleev xim thiab lwm yam haujlwm.
Saib mus rau yav tom ntej, nws hais tias:" Yav tom ntej, peb npaj yuav tsim kho qhov tob tob ultraviolet laser diode (LD) uas tuaj yeem ua tiav lub zog tso zis ntau dua. Yog tias nws tuaj yeem ua tiav, nws tseem yuav tsum tuaj yeem zom cov khoom ntim khoom muaj peev xwm loj thiab cov tshuaj muaj teeb meem uas tshaj li lub peev xwm ntawm Blu-duab tshav Discs."
Qhov chaw txhim kho ntawm tob ultraviolet UVC LED tseem loj heev.
