Ntau tus gamers thoob plaws ntiaj teb uas tau ntsib Xbox 360 era tau paub zoo txog qhov xwm txheej thaum lawv lub console tig mus rau hauv lub lauj kaub kib uas lawv tuaj yeem kib qe. Qhov xwm txheej zoo sib xws tshwm sim tsis yog nrog cov game consoles xwb, tab sis kuj nrog cov xov tooj, laptops, ntsiav tshuaj thiab ntau ntxiv. Raws li txoj cai, yuav luag txhua yam khoom siv hluav taws xob tuaj yeem ua rau muaj kev poob siab, uas tuaj yeem ua rau tsis tsuas yog ua rau nws tsis ua haujlwm thiab chim siab ntawm nws tus tswv, tab sis kuj mus rau "phem boom" ntawm lub roj teeb thiab kev raug mob hnyav. Niaj hnub no peb yuav tau paub txog ib txoj kev tshawb fawb uas cov kws tshawb fawb los ntawm Stanford University, zoo li Nick Fury los ntawm cov comics, tau tsim cov ntaub thaiv npog uas tiv thaiv cov hluav taws xob hluav taws xob los ntawm kev kub dhau thiab, vim li ntawd, tiv thaiv lawv txoj kev tawg. Cov kws tshawb fawb tau tswj hwm li cas los tsim cov ntaub thaiv npog thermal, nws cov khoom tseem ceeb yog dab tsi thiab nws zoo npaum li cas? Peb kawm txog qhov no thiab ntau ntxiv los ntawm tsab ntawv ceeb toom ntawm pawg tshawb fawb. Mus.
Kev tshawb fawb hauv paus
Qhov teeb meem ntawm overheating tau paub ntev heev, thiab cov kws tshawb fawb daws nws hauv ntau txoj hauv kev. Qee qhov nrov tshaj plaws yog kev siv iav, yas thiab txawm tias cov khaubncaws sab nraud povtseg ntawm huab cua, uas yog ib hom insulators ntawm thermal tawg. Hauv kev muaj tiag niaj hnub no, txoj kev no tuaj yeem txhim kho los ntawm kev txo cov thickness ntawm cov txheej tiv thaiv rau ob peb lub atoms yam tsis tau poob nws cov thermal rwb thaiv tsev. Qhov ntawd yog qhov uas cov kws tshawb fawb tau ua.
Peb yog, ntawm chav kawm, tham txog nanomaterials. Txawm li cas los xij, lawv siv hauv thermal rwb thaiv tsev yav tas los nyuaj los ntawm qhov tseeb tias lub wavelength ntawm coolants (phonons*) yog luv luv dua li ntawm electrons lossis photons.
Phonon* - quasiparticle, uas yog quantum ntawm kev vibrational suab ntawm crystal atoms.
Tsis tas li ntawd, vim yog qhov xwm txheej bosonic ntawm phonons, nws tsis tuaj yeem tswj lawv los ntawm qhov hluav taws xob (raws li tau ua nrog cov neeg nqa khoom), uas feem ntau ua rau nws nyuaj rau kev tswj cov cua sov hauv cov khib nyiab.
Yav dhau los, cov khoom cua sov ntawm cov khib nyiab, raws li cov kws tshawb fawb ceeb toom peb, tau tswj los ntawm nanolaminate films thiab superlattices vim kev tsis sib haum xeeb thiab kev sib txuam siab, los yog los ntawm silicon thiab germanium nanowires vim muaj zog phonon tawg.
Rau ib tug xov tooj ntawm cov thermal rwb thaiv tsev txoj kev uas tau piav saum toj no, cov kws tshawb fawb muaj kev ntseeg siab tau npaj rau cov khoom siv ob-seem, cov tuab uas tsis pub tshaj ob peb atoms, uas ua rau lawv yooj yim los tswj ntawm atomic scale. Hauv lawv txoj kev kawm lawv tau siv van der Waals (vdW) sib dhos ntawm atomically nyias 2D khaubncaws sab nraud povtseg kom ua tau zoo heev thermal kuj thoob plaws hauv lawv heterostructure.
Van der Waals rog * - intermolecular / interatomic kev sib cuam tshuam nrog lub zog ntawm 10-20 kJ / mol.
Cov txheej txheem tshiab ua rau nws muaj peev xwm kom tau txais cov thermal resistance hauv 2 nm tuab vdW heterostructure piv rau hauv 2 nm tuab SiO300 (silicon dioxide) txheej.
Tsis tas li ntawd, kev siv vdW heterostructures tau ua kom muaj peev xwm tswj tau cov khoom cua sov ntawm qib atomic los ntawm cov txheej txheem ntawm heterogeneous XNUMXD monolayers nrog sib txawv atomic mass densities thiab vibrational hom.
Yog li ntawd, cia peb tsis txhob rub tus miv lub ntsej muag thiab cia peb pib xav txog cov txiaj ntsig ntawm qhov kev tshawb fawb zoo kawg no.
Cov txiaj ntsig tshawb fawb
Ua ntej tshaj plaws, cia peb paub txog cov microstructural thiab optical yam ntxwv ntawm vdW heterostructures siv hauv txoj kev tshawb no.
Duab #1
Ntawm daim duab 1 qhia ib daim duab kab ke ntawm plaub-txheej heterostructure uas muaj (los ntawm sab saum toj mus rau hauv qab): graphene (Gr), MoSe2, MoS2, WSe22 thiab SiO2 / Si substrate. Txhawm rau luam theej duab txhua txheej ib txhij, siv Raman laser * nrog lub wavelength ntawm 532 nm.
Raman laser * - ib hom laser nyob rau hauv uas lub ntsiab mechanism ntawm lub teeb amplification yog Raman tawg.
Raman tawg, nyob rau hauv lem, yog lub inelastic scattering ntawm optical hluav taws xob nyob rau hauv lub molecules ntawm ib yam khoom, uas yog nrog los ntawm ib tug tseem ceeb kev hloov nyob rau hauv lub zaus ntawm hluav taws xob.
Ntau txoj hauv kev tau siv los lees paub qhov microstructural, thermal thiab hluav taws xob homogeneity ntawm heterostructures: scanning kis electron microscopy (STEM), photoluminescence spectroscopy (PL), Kelvin sojntsuam microscopy (KPM), scanning thermal microscopy (SThM), nrog rau Raman spectroscopy thiab tus pas ntsuas kub.
Image Duab 1b qhia peb Raman spectrum ntawm Gr/MoSe2/MoS2/WSe22 heterostructure ntawm SiO2/Si substrate ntawm qhov chaw uas cim nrog ib tug liab dot. Cov phiaj xwm no qhia txog kev kos npe ntawm txhua tus monolayer hauv txheej array, nrog rau kos npe ntawm Si substrate.
rau 1c-1f dark-field STEM dluab ntawm Gr/MoSe2/MoS2/WSe22 heterostructure yog qhia (1c ib) thiab Gr/MoS2/WSe22 heterostructures (1d-1f) nrog txawv lattice orientations. STEM dluab qhia atomically kaw vdW qhov khoob uas tsis muaj kev kis kab mob, tso cai rau tag nrho cov tuab ntawm cov heterostructures pom tag nrho. Lub xub ntiag ntawm interlayer coupling kuj tau lees paub nyob rau thaj tsam loj scanning siv photoluminescence (PL) spectroscopy (1g). Lub teeb liab photoluminescent ntawm ib tug neeg txheej nyob rau hauv lub heterostructure yog heev suppressed piv rau lub teeb liab ntawm ib tug cais monolayer. Qhov no tau piav qhia los ntawm cov txheej txheem ntawm interlayer tus nqi hloov pauv vim yog kev sib cuam tshuam interlayer, uas ua rau muaj zog dua tom qab annealing.
Duab #2
Txhawm rau ntsuas cov cua sov ntws mus rau qhov nruab nrab ntawm lub dav hlau atomic ntawm heterostructure, array ntawm txheej tau tsim nyob rau hauv daim ntawv ntawm plaub-kev sojntsuam cov khoom siv hluav taws xob. Sab saum toj txheej ntawm graphene hu palladium (Pd) electrodes thiab yog siv los ua lub rhaub rau Raman thermometry ntsuas.
Txoj kev siv hluav taws xob cua sov no muab qhov tseeb kom muaj nuj nqis ntawm lub zog nkag. Lwm txoj kev ua cua sov, kho qhov muag, yuav nyuaj dua rau kev siv vim tsis paub txog kev nqus coefficients ntawm cov txheej txheem ib leeg.
rau 2 qhia tau hais tias plaub-kev sojntsuam ntsuas Circuit Court, thiab 2b qhia pom sab saum toj ntawm cov qauv raug sim. Teem caij 2c ib qhia tau hais tias ntsuas kub hloov cov yam ntxwv rau peb li, ib qho tsuas muaj graphene thiab ob muaj Gr/WSe22 thiab Gr/MoSe2/WSe22 txheej arrays. Txhua qhov kev hloov pauv qhia txog tus cwj pwm tsis zoo ntawm graphene, uas cuam tshuam nrog qhov tsis muaj qhov sib txawv.
Nws kuj tau pom tias tam sim no conduction thiab cua sov tshwm sim nyob rau hauv lub sab sauv txheej (graphene), vim nws cov hluav taws xob conductivity yog ob peb txiav txim ntawm magnitude siab tshaj li ntawm MoS2 thiab WSe22.
Txhawm rau ua kom pom qhov sib xws ntawm cov khoom siv kuaj, ntsuas tau siv Kelvin sojntsuam microscopy (KPM) thiab scanning thermal microscopy (SThM). Ntawm daim duab 2d KPM ntsuas tau tso tawm qhia pom cov kab muaj peev xwm faib tawm. Cov txiaj ntsig ntawm SThM tsom xam tau pom hauv 2s ua. Ntawm no peb pom ib daim ntawv qhia ntawm cov hluav taws xob cua sov Gr/MoS2/WSe22 raws, nrog rau qhov muaj qhov sib xws hauv cov cua sov saum npoo.
Cov txheej txheem scanning tau piav saum toj no, tshwj xeeb tshaj yog SThM, tau lees paub qhov sib xws ntawm cov qauv hauv kev kawm, uas yog, nws qhov sib xws, ntawm qhov kub thiab txias. Cov kauj ruam tom ntej yog kom ntsuas qhov ntsuas kub ntawm txhua txheej txheej txheej siv Raman spectroscopy (piv txwv li, Raman spectroscopy).
Tag nrho peb cov cuab yeej tau sim, txhua qhov muaj thaj tsam ntawm ~ 40 Β΅m2. Nyob rau hauv cov ntaub ntawv no, lub rhaub lub hwj chim hloov los ntawm 9 mW, thiab lub absorbed laser hwj chim yog qis dua ~ 5 ΞΌW nrog ib tug laser chaw ntawm ~ 0.5 ΞΌm2.
Duab #3
Ntawm daim duab 3 qhov nce ntawm qhov kub thiab txias (βT) ntawm txhua txheej thiab substrate yog pom raws li lub rhaub fais fab hauv Gr/MoS2/WSe22 heterostructure nce.
Qhov nqes hav ntawm txoj kab ua haujlwm rau txhua yam khoom (txheej txheem) qhia qhov thermal kuj (Rth = βT / P) ntawm tus kheej txheej thiab lub dab dej kub. Muab qhov sib faib ntawm cov cua sov ntawm thaj chaw, thermal resistances tau yooj yim txheeb xyuas los ntawm hauv qab mus rau sab saum toj txheej, thaum lub sij hawm lawv cov nuj nqis yog normalized los ntawm cov channel cheeb tsam (WL).
L thiab W yog cov channel ntev thiab dav, uas yog qhov ntau dua li cov tuab ntawm SiO2 substrate thiab sab nraud thermal cua sov ntev, uas yog ~ 0.1 ΞΌm.
Yog li ntawd, peb tuaj yeem muab cov qauv rau cov thermal tsis kam ntawm Si substrate, uas yuav zoo li no:
Rth, Si β (WL) 1/2 / (2kSi)
Hauv qhov xwm txheej no kSi β 90 W mβ1 Kβ1, uas yog qhov kev cia siab thermal conductivity ntawm xws li ib tug heev doped substrate.
Qhov sib txawv ntawm Rth, WSe2 thiab Rth, Si yog qhov sib npaug ntawm cov thermal kuj ntawm 2 nm tuab SiO100 thiab thermal ciam teb tsis kam (TBR) ntawm WSe2 / SiO2 interface.
Muab tag nrho cov saum toj no ua ke, peb tuaj yeem tsim tau tias Rth, MoS2 β Rth, WSe2 = TBRMoS2/WSe2, thiab Rth, Gr β Rth, MoS2 = TBRGr/MoS2. Yog li ntawd, los ntawm daim duab 3 Nws muaj peev xwm rho tawm tus nqi TBR rau txhua qhov WSe2/SiO2, MoS2/WSe2 thiab Gr/MoS2 interfaces.
Tom ntej no, cov kws tshawb fawb piv rau tag nrho cov thermal tsis kam ntawm tag nrho cov heterostructures, ntsuas siv Raman spectroscopy thiab thermal microscopy (3b).
Bilayer thiab trilayer heterostructures ntawm SiO2 pom zoo thermal kuj nyob rau hauv thaj tsam ntawm 220 mus rau 280 m2 K / GW ntawm chav tsev kub, uas yog sib npaug rau thermal kuj ntawm SiO2 nrog ib tug tuab ntawm 290 mus rau 360 nm. Txawm tias muaj tseeb hais tias lub thickness ntawm lub heterostructures nyob rau hauv kev kawm tsis ntau tshaj 2 nm (1d-1f), lawv thermal conductivity yog 0.007-0.009 W m-1 K-1 ntawm chav tsev kub.
Duab #4
Daim duab 4 qhia txog kev ntsuas ntawm tag nrho plaub lub qauv thiab cov thermal ciam teb conductivity (TBC) ntawm lawv cov kev sib tshuam, uas tso cai rau peb los ntsuas qhov ntsuas ntawm txhua txheej ntawm qhov ntsuas yav dhau los thermal resistance (TBC = 1 / TBR).
Cov kws tshawb fawb tau sau tseg tias qhov no yog thawj qhov kev ntsuas TBC rau atomically sib cuam tshuam ntawm cov monolayers cais (2D / 2D), tshwj xeeb ntawm WSe2 thiab SiO2 monolayers.
TBC ntawm monolayer WSe2 / SiO2 interface yog qis dua li ntawm multilayer WSe2 / SiO2 interface, uas tsis yog qhov xav tsis thoob vim tias cov monolayer muaj tsawg dua bending phonon hom muaj rau kev sib kis. Yooj yim muab tso, TBC ntawm qhov sib txuas ntawm 2D txheej yog qis dua TBC ntawm qhov sib txuas ntawm 2D txheej thiab 3D SiO2 substrate (4b).
Rau cov ncauj lus kom ntxaws ntxiv nrog cov nuances ntawm txoj kev tshawb no, kuv xav kom saib ΠΈ rau nws.
Epilogue
Qhov kev tshawb fawb no, raws li cov kws tshawb fawb lawv tus kheej tau hais, muab kev paub rau peb uas tuaj yeem siv rau hauv kev siv atomic thermal interfaces. Qhov kev ua haujlwm no tau pom qhov ua tau ntawm kev tsim cov hluav taws kub-insulating metamaterials uas nws cov khoom tsis pom nyob rau hauv qhov xwm txheej. Tsis tas li ntawd, txoj kev tshawb fawb kuj tau lees paub qhov muaj peev xwm ua tiav qhov ntsuas qhov ntsuas kub ntawm cov qauv no, txawm tias qhov ntsuas atomic ntawm cov txheej.
Cov heterostructures tau piav saum toj no tuaj yeem dhau los ua lub hauv paus rau ultra-teeb thiab compact thermal "shields", muaj peev xwm, piv txwv li, tshem tawm cov cua sov los ntawm cov chaw kub hauv hluav taws xob. Tsis tas li ntawd, cov thev naus laus zis no tuaj yeem siv rau hauv cov tshuab hluav taws xob thermoelectric lossis cov khoom siv thermally tswj, ua kom lawv cov kev ua tau zoo.
Txoj kev tshawb no ib zaug tau lees paub tias kev tshawb fawb niaj hnub no txaus siab rau lub hauv paus ntsiab lus ntawm "kev ua tau zoo hauv lub thimble," uas tsis tuaj yeem hu ua lub tswv yim ruam, muab cov peev txheej tsawg ntawm lub ntiaj teb thiab kev loj hlob tsis tu ncua hauv kev thov rau txhua yam kev tsim kho thev naus laus zis.
Ua tsaug rau kev nyeem ntawv, nyob xav paub thiab muaj lub lim tiam zoo! π
Ua tsaug uas koj nyob nrog peb. Koj puas nyiam peb cov ntawv? Xav pom cov ntsiab lus nthuav ntxiv? Txhawb nqa peb los ntawm kev tso ib qho kev txiav txim lossis qhia rau cov phooj ywg, 30% luv nqi rau cov neeg siv Habr ntawm qhov tshwj xeeb analogue ntawm nkag-theem servers, uas tau tsim los ntawm peb rau koj: (muaj nrog RAID1 thiab RAID10, mus txog 24 cores thiab mus txog 40GB DDR4).
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