Abadlali abaninzi behlabathi abanamava eXbox 360 baqhelene kakhulu nemeko xa i-console yabo yajika yaba yipani yokuqhotsa ababenokuqhotsa amaqanda kuyo. Imeko efanayo elusizi ayenzeki kuphela ngee-consoles zomdlalo, kodwa kunye neefowuni, iilaptops, iitafile kunye nokunye okuninzi. Ngokomgaqo, phantse nasiphi na isixhobo sombane sinokufumana ukutshatyalaliswa kwe-thermal, okungakhokelela kuphela ekungaphumeleli kwayo kunye nokucaphukisa umnini wayo, kodwa "kwi-boom embi" yebhetri kunye nokulimala okukhulu. Namhlanje siza kuqhelana nophononongo apho izazinzulu ezivela kwiYunivesithi yaseStanford, njengoNick Fury ovela kumahlaya, zenze ikhaka elikhusela iindawo ze-elektroniki ezingevani nobushushu ekutshiseni kakhulu kwaye, ngenxa yoko, zithintele ukuqhekeka kwazo. Izazinzulu ziye zakwazi njani ukwenza i-thermal shield, ziphi iindawo zayo eziphambili kwaye zisebenza kangakanani? Sifunda malunga noku kunye nokunye kwingxelo yeqela lophando. Hamba.
Isiseko sophando
Ingxaki yokushisa ngokugqithiseleyo iyaziwa ixesha elide, kwaye izazinzulu ziyayicombulula ngeendlela ezahlukeneyo. Ezinye zezona zidumileyo kukusetyenziswa kweglasi, iplastiki kunye neengqimba zomoya, ezisebenza njengoluhlobo lwe-insulators yemitha ye-thermal. Kwiinyani zanamhlanje, le ndlela inokuphuculwa ngokunciphisa ubukhulu bomgangatho okhuselayo kwii-athomu ezininzi ngaphandle kokulahlekelwa iimpawu zayo zokugquma i-thermal. Yiloo nto kanye eyenziwa ngabaphandi.
Ngokuqinisekileyo, sithetha ngama-nanomaterials. Nangona kunjalo, ukusetyenziswa kwabo kwi-thermal insulation ngaphambili kwakunzima ngenxa yokuba ubude bezinto ezipholileyo (iiphonon*) mfutshane kakhulu kunee-electron okanye iifotoni.
iPhonon* - i-quasiparticle, eyi-quantum yentshukumo ye-vibrational yee-athomu ze-crystal.
Ukongezelela, ngenxa yobume be-bosonic yeephonon, akunakwenzeka ukuzilawula nge-voltage (njengoko kusenziwa ngabathwali bentlawulo), ngokuqhelekileyo kwenza kube nzima ukulawula ukuhanjiswa kobushushu kwizinto eziqinileyo.
Ngaphambili, iipropati ze-thermal ze-solids, njengoko abaphandi besikhumbuza, zilawulwa ngeefilimu ze-nanolaminate kunye ne-superlattices ngenxa yokuphazamiseka kwesakhiwo kunye ne-interfaces yoxinaniso oluphezulu, okanye nge-silicon kunye ne-germanium nanowires ngenxa yokusabalalisa i-phonon enamandla.
Kwinani leendlela zokufakelwa kwe-thermal ezichazwe ngasentla, izazinzulu zilungele ukulungelelanisa izinto ezi-dimensional-dimensional, ubukhulu bawo abudluli ii-athomu ezininzi, okwenza kube lula ukulawula kwisikali se-athomu. Kwisifundo sabo basebenzise van der Waals (vdW) indibano yomaleko we-atomically obhityileyo we-2D ukufikelela kuxhathiso oluphezulu kakhulu lwe-thermal kuyo yonke i-heterostructure yabo.
Imikhosi kaVan der Waals* - i-intermolecular / interatomic interaction forces kunye namandla e-10-20 kJ / mol.
Ubuchule obutsha buye benza ukuba kufumaneke ukuxhathisa kwe-thermal kwi-2 nm engqingqwa ye-vdW heterostructure enokuthelekiswa naleyo iku-2 nm engqindilili ye-SiO300 (i-silicon dioxide) umaleko.
Ukongeza, ukusetyenziswa kwee-heterostructures ze-vdW kwenze ukuba kube lula ukufumana ulawulo kwiipropati zokushisa kwinqanaba le-athomu ngokubekwa kwee-monolayers ze-XNUMXD ezahlukeneyo ezinobunzima be-athomu kunye neendlela zokungcangcazela.
Ngoko ke, masingatsali amabhovu ekati kwaye masiqale ukuqwalasela iziphumo zolu phando lumangalisayo.
Iziphumo zophando
Okokuqala, makhe siqhelane neempawu ze-microstructural kunye ne-optical ye-vdW heterostructures esetyenziswe kwesi sifundo.
Umfanekiso #1
Kumfanekiso 1 ibonisa umzobo we-cross-sectional we-heterostructure ene-four equkethe (ukusuka phezulu ukuya ezantsi): igraphene (Gr), i-MoSe2, i-MoS2, i-WSe22 kunye ne-SiO2 / Si substrate. Ukuskena zonke iileya ngaxeshanye, sebenzisa Raman laser* kunye nobude be-532 nm.
Raman laser* - uhlobo lwe-laser apho indlela ephambili yokwandisa ukukhanya yiRaman yokusabalalisa.
URaman uyachithachitha, kwakhona, ukusasazeka kwe-inelastic yemitha ye-optical kwi-molecule ye-substance, ehamba kunye notshintsho oluphawulekayo kwi-frequency ye-radiation.
Iindlela ezininzi zasetyenziselwa ukuqinisekisa i-microstructural, i-thermal kunye ne-homogeneity yombane ye-heterostructures: ukuskena ukuhanjiswa kwe-electron microscopy (STEM), i-photoluminescence spectroscopy (PL), i-Kelvin probe microscopy (KPM), ukuskena i-microscopy ye-thermal (SThM), kunye ne-Raman spectroscopy kunye thermometry .
Umfanekiso 1b isibonisa i-Raman spectrum ye-Gr/MoSe2/MoS2/WSe22 heterostructure kwi-SiO2/Si substrate kwindawo ephawulwe ngechaphaza elibomvu. Eli cebo libonisa utyikityo lwe-monolayer nganye kuluhlu lwamaleko, kunye nokutyikitya kwe-Si substrate.
phezu 1c-1f Imifanekiso yeSTEM yentsimi emnyama ye-Gr/MoSe2/MoS2/WSe22 heterostructure iyaboniswa (1s) kunye ne-Gr/MoS2/WSe22 heterostructures (1d-1f) ngokuqhelaniswa nelathisi okwahlukeneyo. Imifanekiso ye-STEM ibonisa izithuba ezivale i-athom ye-vdW ngaphandle kokungcoliseka, ivumela ubukhulu obupheleleyo bezi heterostructures ukuba bubonakale ngokupheleleyo. Ubukho bokudityaniswa kwe-interlayer buqinisekisiwe kwiindawo ezinkulu zokuskena kusetyenziswa i-photoluminescence (PL) spectroscopy (1g). Isignali ye-photoluminescent yeengqimba zomntu ngamnye ngaphakathi kwe-heterostructure igxininiswe kakhulu xa kuthelekiswa nomqondiso we-monolayer eyedwa. Oku kucaciswa yinkqubo yokudluliselwa kwentlawulo ye-interlayer ngenxa yentsebenziswano esondeleyo ye-interlayer, ethi ibe namandla ngakumbi emva kokuqhawula.
Umfanekiso #2
Ukuze ulinganise ukuhamba kobushushu kwi-perpendicular kwiiplani ze-athomu ze-heterostructure, uluhlu lwemigangatho lwakhiwe ngendlela yezixhobo zombane ezine-probe. Umaleko ophezulu wegraphene contacts palladium (Pd) electrode kwaye isetyenziswa njengesifudumezi seRaman thermometry imilinganiselo.
Le ndlela yokufudumala yombane ibonelela ngobungakanani obuchanekileyo bamandla okufaka. Enye indlela yokufudumeza enokwenzeka, i-optical, iya kuba nzima ngakumbi ukuyiphumeza ngenxa yokungazi kakuhle i-coefficients yokufunxa yamacandelo ngamnye.
phezu 2 ibonisa isiphaluka somlinganiselo weprobe ezine, kunye 2b ibonisa imbonakalo ephezulu yesakhiwo esivavanywayo. Ishedyuli 2s ibonisa iimpawu zokutshintsha ubushushu obulinganisiweyo kwizixhobo ezithathu, esinye siqulethe kuphela igraphene kwaye ezimbini ziqulethe i-Gr/WSe22 kunye ne-Gr/MoSe2/WSe22 umaleko woluhlu. Zonke izinto ezahlukeneyo zibonisa ukuziphatha okumbi kwegraphene, enxulunyaniswa nokungabikho komsantsa webhendi.
Kwakhona kwafunyaniswa ukuba ukuqhutyelwa kwangoku kunye nokufudumeza kwenzeka kwinqanaba eliphezulu (kwi-graphene), ekubeni ukuhanjiswa kombane kwayo kunemiyalelo emininzi yobukhulu obuphezulu kune-MoS2 kunye ne-WSe22.
Ukubonisa i-homogeneity yezixhobo ezivavanyiweyo, imilinganiselo ithathwe kusetyenziswa i-Kelvin probe microscopy (KPM) kunye ne-scanning microscopy ye-thermal (SThM). Kwitshathi 2d Imilinganiselo ye-KPM iyavezwa iveza usasazo olunokwenzeka olunomgca. Iziphumo zohlalutyo lwe-SThM ziboniswe kwi 2s. Apha sibona imephu yeendlela ezifudunyezwe ngombane zeGr/MoS2/WSe22, kunye nobukho bokufana kubushushu bomhlaba.
Iindlela zokuskena ezichazwe ngasentla, ngokukodwa i-SThM, ziqinisekisile i-homogeneity yesakhiwo esiphantsi kophando, oko kukuthi, ukufana kwayo, ngokumalunga namaqondo okushisa. Inyathelo elilandelayo yayikukuba umlinganiselo wobushushu bomaleko ngamnye okhoyo kusetyenziswa iRaman spectroscopy (oko kukuthi, iRaman spectroscopy).
Zontathu izixhobo zavavanywa, ngasinye sinendawo ye ~ 40 Β΅m2. Kule meko, amandla okufudumala atshintshiwe nge-9 mW, kwaye amandla e-laser afunliweyo ayengaphantsi kwe ~ 5 ΞΌW kunye nommandla welaser we ~ 0.5 ΞΌm2.
Umfanekiso #3
Kwitshathi 3 ukunyuka kweqondo lokushisa (βT) kwinqanaba ngalinye kunye ne-substrate kubonakala njengoko amandla okufudumala kwi-heterostructure ye-Gr/MoS2/WSe22 enyuka.
Imithambeka yomsebenzi womgca wento nganye (uluhlu) ibonisa ukuxhathisa kwe-thermal (Rth = βT / P) phakathi komgangatho ngamnye kunye ne-heat sink. Ngenxa yokuhanjiswa okufanayo kokufudumeza kwindawo, ukuchasana kwe-thermal kunokucazululwa ngokulula ukusuka ezantsi ukuya kumaleko aphezulu, ngexesha apho amaxabiso abo aqheleke kwindawo yesitishi (WL).
I-L kunye ne-W ubude bejelo kunye nobubanzi, obukhulu kakhulu kunobukhulu be-substrate ye-SiO2 kunye nobude bokufudumala be-thermal, obuyi ~ 0.1 ΞΌm.
Ke ngoko, sinokufumana ifomula yokumelana ne-thermal ye-Si substrate, eya kujongeka ngolu hlobo:
I-Rth,Si β (WL)1/2 / (2kSi)
Kule meko kSi β 90 W mβ1 Kβ1, eyona ndlela ilindelekileyo ye-thermal conductivity yesubstrate ene-doped kakhulu.
Umahluko phakathi kwe-Rth, i-WSe2 kunye ne-Rth, i-Si sisimbuku sokumelana ne-thermal ye-2 nm ubukhulu be-SiO100 kunye nokumelana nomda we-thermal (TBR) ye-WSe2 / SiO2 interface.
Ukubeka yonke le miba ingasentla kunye, sinokumisela ukuba i-Rth,MoS2 β Rth,WSe2 = TBRMoS2/WSe2, kunye ne-Rth,Gr β Rth,MoS2 = TBRGr/MoS2. Ngoko ke, ukusuka kwigrafu 3 kunokwenzeka ukukhupha ixabiso le-TBR nganye kwi-WSe2/SiO2, i-MoS2/WSe2 kunye ne-Gr/MoS2 ujongano.
Emva koko, izazinzulu zithelekisa ukuchasana kwe-thermal kuzo zonke i-heterostructures, ezilinganiswe kusetyenziswa i-Raman spectroscopy kunye ne-thermal microscopy (3b).
I-Bilayer kunye ne-trilayer heterostructures kwi-SiO2 ibonise ukuxhathisa okusebenzayo kwe-thermal kuluhlu lwe-220 ukuya kwi-280 m2 K / GW kwiqondo lokushisa, elilingana nokumelana ne-thermal ye-SiO2 kunye nobukhulu be-290 ukuya kwi-360 nm. Ngaphandle kwento yokuba ubukhulu be-heterostructures phantsi kophando abukho ngaphezu kwe-2 nm (1d-1f), i-thermal conductivity yabo yi-0.007-0.009 W mβ1 K-1 kwiqondo lokushisa.
Umfanekiso #4
Umfanekiso we-4 ubonisa imilinganiselo yazo zonke izakhiwo ezine kunye ne-thermal boundary conductivity (TBC) ye-interfaces yazo, evumela ukuba sihlolisise iqondo leempembelelo zomaleko ngamnye kwi-recession thermal elinganiswe ngaphambili (TBC = 1 / TBR).
Abaphandi baqaphela ukuba lo ngumlinganiselo wokuqala we-TBC wonxibelelwano olusondeleyo kwi-atomically phakathi kwe-monolayers eyahlukileyo (2D / 2D), ngokukodwa phakathi kwe-WSe2 kunye ne-SiO2 monolayers.
I-TBC ye-monolayer ye-WSe2 / SiO2 i-interface ingaphantsi kune-interface ye-WSe2 / SiO2 ye-multilayer, ayimangalisi kuba i-monolayer ineendlela ezimbalwa zokugoba ze-phonon ezifumanekayo zokusasazwa. Ukubeka ngokulula, i-TBC yojongano phakathi kwe-2D layers ingaphantsi kune-TBC yojongano phakathi kwe-2D layer kunye ne-3D SiO2 substrate (4b).
Ukuze ufumane ulwazi oluthe kratya malunga nee-nuances zophononongo, ndincoma ukujonga ΠΈ kuye.
Ipilo
Olu phando, njengoko izazinzulu zibanga, zisinika ulwazi olunokuthi lusetyenziswe ekuphunyezweni kwe-atomic thermal interfaces. Lo msebenzi ubonise ukuba kunokwenzeka ukudala i-metamatadium ezikhusela ukushisa ezineepropati ezingafumanekiyo kwindalo. Ukongeza, uphononongo lukwaqinisekisile ukuba kunokwenzeka ukwenza imilinganiselo yobushushu echanekileyo yezakhiwo ezinjalo, ngaphandle komlinganiselo we-athomu yomaleko.
I-heterostructures echazwe ngasentla ingaba sisiseko se-ultra-light and compact thermal "shields", ekwaziyo, umzekelo, ukususa ukushisa kwiindawo ezishushu kwi-electronics. Ukongeza, le teknoloji inokusetyenziswa kwiijenereyitha ze-thermoelectric okanye izixhobo ezilawulwa ngokufudumala, ukwandisa ukusebenza kwazo.
Olu phononongo luphinda luqinisekise ukuba isayensi yanamhlanje inomdla kakhulu kumgaqo "wokusebenza kakuhle kwithontsi," ongenakubizwa ngokuba yingcamango yobudenge, ngenxa yobuncwane obulinganiselweyo beplanethi kunye nokukhula okuqhubekayo kwemfuno yazo zonke iintlobo zezinto ezintsha zobuchwepheshe.
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