1 Kev Taw Qhia
Pob zeb diamond muaj cov khoom siv kho qhov muag, kho qhov muag, thermal, thiab hluav taws xob zoo, ua rau nws muaj ntau yam khoom siv nrog rau kev siv dav dav hauv ntau qhov kev siv tshuab siab xws li aerospace, zog, ntse sensors, thiab precision machining [1]. Nrog rau qhov kev thov ntau ntxiv rau pob zeb diamond, pob zeb diamond ntuj reserves yog txwv thiab kim heev, uas tsis tuaj yeem ua tau raws li kev xav tau ntawm kev sib raug zoo. Yog li ntawd, cov kws tshawb fawb tau txuas ntxiv tshawb nrhiav txoj hauv kev tshiab rau kev tsim cov pob zeb diamond artificially.
Cov txheej txheem tseem ceeb rau kev npaj pob zeb diamond hluavtaws yog qhov siab -siab siab-kub (HPHT) txoj kev thiab tshuaj vapor deposition (CVD). Pob zeb diamond particles synthesized los ntawm HPHT txoj kev yog feem ntau me me thiab feem ntau muaj ib tug loj npaum li cas ntawm catalyst impurities. Li no, lawv daim ntawv thov tau txwv, feem ntau yog rau cov khoom siv abrasives thiab cov cuab yeej (xws li, pob zeb diamond polycrystalline, PCD) [2]. Nyob rau hauv xyoo tas los no, chemical vapor deposition (CVD) technology tau tshwm sim los ua qhov kev tshawb fawb tseem ceeb heev. Cov pob zeb diamonds npaj los ntawm CVD muaj qhov ntau thiab tsawg thiab cov duab siv lead ua ze tshaj plaws rau cov pob zeb diamond ntuj thiab nthuav tawm cov khoom zoo heev [3].
2 Kev Npaj Pob Zeb Diamond Films los ntawm CVD
CVD txoj kev yog ib qho tseem ceeb thev naus laus zis rau kev npaj cov yeeb yaj kiab nyias los ntawm kev siv tshuaj. Nws tau siv dav hauv kev npaj ntau yam ntaub ntawv nyias nyias thiab kuj yog ib txoj hauv kev tseem ceeb rau kev tsim cov pob zeb diamond films. Nyob rau hauv xyoo tas los no, kev tshawb fawb ntawm pob zeb diamond zaj duab xis synthesis los ntawm CVD tau nce sai heev, thiab loj - nplai ntau lawm thiab daim ntawv thov muaj peev xwm tam sim no tau ua tiav.
2.1 Kev Loj Hlob Mechanism [4]
CVD synthesis ntawm pob zeb diamond feem ntau cuam tshuam nrog decomposing carbon- muaj cov precursors siv lub zog nyob rau hauv ib tug txo qhov cua los tsim atomic hydrogen, uas pab txhawb pob zeb diamond loj hlob. Cov txheej txheem kev loj hlob tshwj xeeb suav nrog cov kauj ruam hauv qab no: (1) Tus thawj coj (ua piv txwv los ntawm CH₄) tau nkag rau hauv CVD reactor; (2) Lub gaseous precursor yog decomposed los ntawm lub zog (plasma los yog thermal zog) rau hauv dawb radicals (CₓHᵧ, thiab lwm yam); (3) Cov dawb radicals sib tsoo nrog ib leeg kom txog thaum lawv ncav cuag qhov chaw substrate; (4) Dawb radicals adsorb ntawm substrate nto; (5) Cov adsorbed dawb radicals decompose los ua active carbon hom thiab diffuse rau saum npoo; (6) Cov hom nquag tsim cov pob zeb diamond lattice; (7) Tsis yog{10}} hom nquag (xws li hydrogen) desorb los ntawm qhov chaw, tsim hydrogen molecules lossis lwm yam los ntawm- khoom; (8) Los ntawm- cov khoom sib txawv ntawm qhov chaw los ntawm cov ciam teb txheej thiab thaum kawg raug tshem tawm los ntawm cov pa roj ntau.
2.2 Cov txheej txheem npaj
Txij li thaum qhov tshwm sim ntawm CVD pob zeb diamond npaj nyob rau hauv 1980s, cov kws tshawb fawb tau ua raws li nyob rau hauv - kev tshawb fawb tob, ua rau kev txhim kho ntau yam CVD txoj kev [5]. Tam sim no, paub tab pob zeb diamond npaj cov tswv yim muaj xws li kub filament CVD (HFCVD), microwave plasma CVD (MPCVD), thiab ncaj qha tam sim no arc plasma dav hlau CVD (DCPJCVD).
2.2.1 Kub Filament CVD (HFCVD)
Nyob rau hauv txoj kev HFCVD, hydrocarbon gases xws li methane (CH₄) thiab acetylene, ua ke nrog hydrogen (H₂), tau nkag mus rau hauv cov tshuaj tiv thaiv chamber. Cov filament kub nyob rau hauv lub chamber yog siab tshaj 2000 degree, thiab cov roj sib xyaw yog decomposed ntawm qhov kub thiab txias los tsim sp³ hybridized carbon radicals tsim nyog rau pob zeb diamond synthesis, uas tom qab ntawd tsim ib pob zeb diamond zaj duab xis ntawm lub substrate nto [6].
Txoj kev HFCVD muaj qhov zoo ntawm cov cuab yeej siv yooj yim, cov yeeb yaj kiab siab tso tawm tus nqi, kev ua haujlwm yooj yim, tus nqi qis, thiab cov cuab yeej paub tab. Nws tau siv dav hauv kev tsim khoom thiab tseem yog ib txoj hauv kev tseem ceeb rau kev npaj microcrystalline pob zeb diamond txheej, nanocrystalline pob zeb diamond txheej, thiab pob zeb diamond-zoo li carbon coatings [2]. Nws qhov tsis zoo muaj xws li: cov filament kub tsis excite cov roj mus rau qib siab, thiab cov filament nws tus kheej yuav kis tau cov pob zeb diamond zaj duab xis; lub filament yog nquag deformation thaum lub sij hawm cua sov, uas degrades lub uniformity ntawm deposited zaj duab xis; thiab cov filament muaj lub neej luv luv, ua rau nws tsis haum rau ntev - lub sij hawm deposition ntawm tuab zaj duab xis qauv [7].
Tam sim no, kev tshawb fawb ntawm pob zeb diamond zaj duab xis npaj siv HFCVD kuj paub tab ob qho tib si hauv tebchaws thiab thoob ntiaj teb. Txawm li cas los xij, tseem xav tau kev tshawb nrhiav ntxiv txog yuav ua li cas kho cov txheej txheem tsis zoo los txhim kho pob zeb diamond zaj duab xis zoo [2]. Cov txheej txheem tseem ceeb muaj xws li roj ntws tus nqi thiab qhov sib piv, filament kub, substrate hom thiab kub, thiab cov tshuaj tiv thaiv chamber siab.
2.2.2 Direct Current Arc Plasma Jet CVD (DCPJCVD)
Txoj kev DCPJCVD yog ib qho tshwj xeeb CVD pob zeb diamond kev loj hlob cov txheej txheem tsim los ntawm Suav cov kws tshawb fawb [4]. Nws lub hauv paus ntsiab lus yog siv siab - fais fab DC arc tawm los ua kom cov pa tawm ua kom muaj zog feem ntau yog tsim los ntawm CH₄-H₂-Ar rau hauv cov ntshav, uas tom qab ntawd raug tshem tawm ntawm kev kub ceev mus rau qhov chaw substrate, tso lub pob zeb diamond zaj duab xis [7].
Piv nrog rau lwm cov txheej txheem CVD deposition, DCPJCVD muaj qhov zoo ntawm qhov zoo tshaj plaws deposition tus nqi, tsis tshua muaj paug voltage, siab paug tam sim no, siab ionization degree, siab plasma ceev, thiab loj deposition cheeb tsam. Nws qhov kev tso nyiaj ntau tshaj plaws tuaj yeem ncav cuag 1000 μm / h, ua rau nws tsim nyog rau kev tsim cov yeeb yaj kiab loj - cheeb tsam pob zeb diamond. Tam sim no nws yog txoj hauv kev nrawm tshaj plaws rau kev sib xyaw cov yeeb yaj kiab pob zeb diamond, tab sis nws yuav tsum muaj cov cuab yeej siv tseem ceeb, kev ua haujlwm nyuaj, thiab cov yeeb yaj kiab sib xws tseem xav tau kev txhim kho [4].
Hauv Suav teb, University of Science thiab Technology Beijing thiab Hebei Academy ntawm Kev Tshawb Fawb tau koom ua ke tsim thiab kho cov thev naus laus zis no [8]. Tam sim no, pob zeb diamond films npaj los ntawm DC arc plasma jet technology nyob rau hauv Tuam Tshoj yog nyob rau hauv ib tug advanced theem nyob rau hauv cov nqe lus ntawm zoo thiab cheeb tsam piv rau cov uas tsim los ntawm tib txoj kev txawv teb chaws, thiab lwm yam pob zeb diamond zaj duab xis cov khoom twb tau nkag mus rau hauv lub thoob ntiaj teb kev ua lag luam nyob rau hauv bulk raws li superhard cuab yeej.
2.2.3 Microwave Plasma CVD (MPCVD)
Hauv MPCVD txoj kev npaj rau pob zeb diamond zaj duab xis, qhov siab - zaus electromagnetic teb tsim los ntawm microwave magnetron ua rau electrons oscillate vigorously nyob rau hauv ib qho chaw kaw. Cov electrons no sib tsoo nrog cov roj molecules thiab atoms nyob rau hauv qhov chaw, ionizing cov pa thiab tsim cov active radicals xws li -CH₃ thiab H. Cov active hom no undergo physicochemical tshua, txav mus rau hauv lub substrate, thiab ces adsorb, diffuse, nucleate, thiab loj hlob nyob rau hauv lub substrate nto.
Ib qho tseem ceeb ntawm MPCVD yog tias lub microwave plasma tuaj yeem ua tiav qhov kev tso tawm ruaj khov yam tsis muaj electrodes ntawm qhov siab - zaus hluav taws xob, yog li txo cov qauv paug. In addition, the microwave causes vigorous gas oscillation, effectively activating the gas and generating high-density plasma, which enables the growth of high-quality diamond films [10]. Qhov nyuaj yog nyob rau hauv kev tsim ib cheeb tsam loj thiab zoo ib yam deposition, uas yog cuam tshuam los ntawm ntau yam, nrog rau cov hluav taws xob teb faib nyob rau hauv cov kab noj hniav, substrate kub variation, microwave hwj chim, thiab kev faib tawm ntawm active radicals. Ntxiv mus, lub pob zeb diamond zaj duab xis deposition feem ntau yog qis dua li ntawm DC arc plasma dav hlau CVD [4].
Txhawm rau them nyiaj rau qhov qis qis ntawm MPCVD, cov kws tshawb fawb txawv teb chaws tau nce lub zog nkag ntawm cov cuab yeej los txhim kho tus nqi tso nyiaj. Ntau xyoo dhau los ntawm txoj kev loj hlob, lub zog tau nce los ntawm ob peb puas watts mus txog ze li ntawm 100 kW, txhim kho qhov chaw tso nyiaj, qhov tso nyiaj tau zoo, thiab cov yeeb yaj kiab pob zeb diamond zoo. Kev tshawb fawb hauv tsev ntawm MPCVD pob zeb diamond npaj tau pib lig, tab sis dhau los ntawm kev tshawb fawb thiab kev txhim kho txuas ntxiv, Tuam Tshoj tau ua kom nrawm nrog kev vam meej thoob ntiaj teb, txawm tias qhov sib txawv tseem nyob hauv cov ntawv thov kev lag luam thiab kev lag luam. Hauv 20 xyoo dhau los, pab pawg tshawb fawb hauv tsev tau tsom mus rau kev tsim kho resonator kom nrhiav loj- nplai kev lag luam pob zeb diamond [11].
3 Daim ntawv thov ntawm Pob Zeb Diamond Films
3.1 Kev siv kho qhov muag
Cov yeeb yaj kiab pob zeb diamond muaj cov khoom siv kho qhov muag zoo heev, suav nrog kev xa tawm siab, qis refractive index, thiab qis tawg. Lawv feem ntau yog siv los tsim cov qhov rais kho qhov muag, qhov muag qhov muag, thiab lwm yam khoom, nrog rau cov ntawv thov kev cia siab nyob rau hauv siab -tech fields xws li tub rog, kev sib txuas lus, thiab satellite technology. Cov yeeb yaj kiab pob zeb diamond muaj cov khoom zoo ntawm lub cev, tshwj xeeb tshaj yog kev xa tawm zoo los ntawm ultraviolet mus rau qhov deb -infrared thiab microwave ntau. Thaum siv rau cov qhov rais kho qhov muag, lawv tuaj yeem zam qhov cuam tshuam ntawm lub lens thermal, nag yaig, xuab zeb yaig, thiab kho qhov muag tsis pom kev. Tsis tas li ntawd, cov yeeb yaj kiab pob zeb diamond feem ntau yog siv hauv X-ray windows thiab lub qhov ncauj qhov ntswg, X-ray transmission targets, optical lenses, thiab lwm yam khoom siv [12].
3.2 Thermal Applications
Yav dhau los, kev kub ceev, siab zog, thiab ntim me me tau dhau los ua cov kev xav tsis tu ncua hauv kev tsim cov khoom siv hluav taws xob hauv microelectronics. Txawm li cas los xij, nrog cov qauv no, cov cua sov tsim los ntawm cov khoom siv yuav nce ntau. CVD pob zeb diamond films muaj cov khoom sib piv rau cov pob zeb diamond ntuj, tshwj xeeb tshaj yog cov coefficient qis heev ntawm thermal expansion, ultra-siab thermal conductivity, thiab hluav taws xob rwb thaiv tsev. Lawv yog cov khoom siv hluav taws xob zoo tshaj plaws thiab cov khoom ntim khoom, dav siv nyob rau hauv siab - lub zog laser, loj- nplai kev sib txuas, RF fais fab transistors, siab - lub hwj chim kho qhov muag, thiab lwm yam khoom siv.
3.3 Acoustic Applications
Nrog rau kev siv dav dav ntawm cov khoom siv suab, cov neeg siv khoom xav tau rau cov neeg hais lus zoo tau nce tsis tu ncua. Piv nrog rau cov khoom siv diaphragm ib txwm muaj xws li carbon fiber, ceramic, thiab beryllium, pob zeb diamond films tau qis dua thiab ntau dua elastic modulus. Nyob rau tib lub sijhawm, cov kab lis kev cai hauv polycrystalline pob zeb diamond films tuaj yeem muab kev sib txhuam sab hauv zoo tagnrho, muab cov khoom zoo tshaj plaws rau cov khoom siv ib txwm siv, ua pob zeb diamond yog qhov kev xaiv zoo tshaj plaws rau kev hais lus diaphragms. Tsis tas li ntawd, kev siv cov xov xwm acoustic siab tshaj tawm yog ib qho tseem ceeb ntawm kev ua haujlwm ntawm cov khoom siv ntau zaus. Pob zeb diamond yog tam sim no cov khoom siv nrog lub siab tshaj plaws paub acoustic propagation tshaj tawm, uas tuaj yeem txhim kho qhov kev khiav hauj lwm zaus ntawm qhov chaw acoustic yoj (SAW) cov cuab yeej, ua kom muaj kev sib cuam tshuam ntawm RF teeb liab thiab kev vibrations, thiab muab cov ntawv thov dav dav hauv satellite, kev sib txuas lus ntawm tes, thiab lwm yam [10].
3.4 Kev siv hluav taws xob
Vim lub pob zeb diamonds dav bandgap, siab electron thiab qhov txav, siab tawg hluav taws xob teb, tsis tshua muaj hluav taws xob tsis tu ncua, siab resistivity, thiab siab thermal conductivity, nws yog qhov tsim nyog rau cov khoom siv semiconductor sib xyaw ua haujlwm nyob rau hauv qhov kub, siab bias, siab zog, thiab hluav taws xob siab. Yog li ntawd, pob zeb diamond yuav tsum tau hloov silicon raws li cov khoom siv zoo tshaj plaws rau cov khoom siv hluav taws xob uas yuav tsum muaj kev ntseeg siab hauv cov xwm txheej hnyav xws li kub kub thiab hluav taws xob tiv thaiv.
3.5 Biomedical Applications
Pob zeb diamond films ua ke zoo biocompatibility, zoo heev mechanical zog, thiab chemical stability, ua rau lawv muaj kev vam meej tom ntej no - tiam biomaterials. Lawv cov khoom siv zoo tshaj plaws thiab tshuaj lom neeg ruaj khov tuaj yeem txo qhov hnav thiab electrochemical corrosion ntawm pob zeb diamond -coated implants. Kev hloov pauv ntawm qhov chaw, biocompatibility, thiab cov khoom siv hluav taws xob zoo heev tom qab doping ntawm CVD pob zeb diamond films kuj ua rau lawv zoo heev txhawb rau biosensors. Piv nrog rau lwm cov kev txhawb nqa, biosensors raws li pob zeb diamond zaj duab xis substrates muaj kev ruaj ntseg dua, kev ntseeg siab, thiab rhiab heev.