Vatambi vazhinji kutenderera pasirese vakawana nguva yeXbox 360 vanonyatsoziva mamiriro ezvinhu apo koni yavo yakashanduka kuita pani yekubikisa mavaigona kugocha mazai. Mamiriro akafanana anosiririsa anoitika kwete chete nemitambo consoles, asiwo nemafoni, malaptop, mahwendefa uye zvimwe zvakawanda. Muchidimbu, chinenge chero chigadzirwa chemagetsi chinogona kuona kupisa kwekushisa, izvo zvinogona kutungamirira kwete kungokundikana uye kugumburwa kwemuridzi wayo, asiwo kune "bad boom" yebhatiri uye kukuvara kwakakomba. Nhasi tichajairana nekudzidza umo masayendisiti kubva kuStanford University, saNick Fury kubva kumakomiki, vakagadzira nhoo inodzivirira kupisa-sensitive emagetsi zvikamu kubva pakupisa uye, semhedzisiro, inodzivirira kubva kutyora. Masayendisiti akakwanisa sei kugadzira nhovo yekushisa, ndezvipi zvikamu zvayo zvikuru uye inoshanda sei? Tinodzidza pamusoro peizvi uye nezvimwe kubva mumushumo weboka rekutsvakurudza. Enda.
Hwaro hwechidzidzo
Dambudziko rekupisa rave richizivikanwa kwenguva yakareba, uye masayendisiti anogadzirisa nenzira dzakasiyana-siyana. Zvimwe zvezvinonyanya kufarirwa ndezvekushandiswa kwegirazi, mapurasitiki uye kunyange zvidimbu zvemhepo, izvo zvinoshanda semhando yezvidziviriro zvekupisa kwemwaranzi. Muchokwadi chemazuva ano, nzira iyi inogona kuvandudzwa nekudzikisa ukobvu hwechidziviriro layer kune akati wandei maatomu pasina kurasikirwa nekupisa kwayo. Ndizvo chaizvo zvakaitwa nevatsvakurudzi.
Isu tiri, chokwadi, kutaura nezve nanomaterials. Nekudaro, kushandiswa kwavo mukupisa kwemafuta kwakamboomeswa nenyaya yekuti wavelength yezvinotonhorera (maphononi*) ipfupi zvakanyanya pane iyo yemaerekitironi kana mafotoni.
Phononi* - quasiparticle, inova quantum yekufamba kwekudengenyeka kwemaatomu ekristaro.
Mukuwedzera, nekuda kwechimiro chebhosonic yemaphononi, hazvibviri kuadzora nemagetsi (sezvinoitwa nevatakuri vechaji), izvo zvinowanzoita kuti zviome kudzora kupisa kwekushisa muzvakaoma.
Kare, izvo zvinopisa zvezvakaoma, sezvatinoyeuchidzwa nevatsvakurudzi, zvaidzorwa kuburikidza ne nanolaminate mafirimu uye superlattices nekuda kwekusagadzikana kwemaitiro uye high density interfaces, kana kuburikidza nesilicon uye germanium nanowires nekuda kwekupararira kwephonon yakasimba.
Kune akati wandei enzira dzekudzivirira kupisa kwemafuta anotsanangurwa pamusoro, masayendisiti akagadzirira nechivimbo kutaura zvinhu zvine mativi maviri, ukobvu hwayo husingapfuuri maatomu akati wandei, izvo zvinoita kuti zvive nyore kudzora pachiyero cheatomu. Mukudzidza kwavo vakashandisa van der Waals (vdW) gungano reatomu yakatetepa 2D akaturikidzana kuti awane yakakwira kwazvo kupisa kwekudzivirira mukati meheterostructure yavo.
Van der Waals forces* - intermolecular / interatomic kupindirana masimba ane simba re 10-20 kJ / mol.
Nzira itsva iyi yakaita kuti zvikwanisike kuwana kupisa kwekushisa mu 2 nm gobvu vdW heterostructure inofananidzwa neiyo mu2 nm gobvu SiO300 (silicon dioxide) layer.
Pamusoro pezvo, kushandiswa kwevdW heterostructures kwaita kuti zvikwanise kuwana kutonga pamusoro pezvinhu zvinopisa padanho reatomu kuburikidza nekuiswa kweheterogeneous XNUMXD monolayers ane akasiyana atomic mass densities uye vibrational modes.
Saka, ngatirege kudhonza ndebvu dzekatsi uye ngatitange kufunga nezvemigumisiro yeiyi tsvakurudzo inoshamisa.
Mhedzisiro yekutsvaga
Chekutanga, ngatizivei nezve microstructural uye optical maitiro evdW heterostructures anoshandiswa muchidzidzo ichi.
Mufananidzo #1
Mumufananidzo 1a inoratidza dhayagiramu yemuchinjikwa yechina-layer heterostructure inosanganisira (kubva kumusoro kusvika pasi): graphene (Gr), MoSe2, MoS2, WSe22 uye SiO2/Si substrate. Kuti utarise maseru ese panguva imwe chete, shandisa Raman laser* ine wavelength ye532 nm.
Raman laser* - rudzi rwelaser umo iyo huru meshini yekusimudza mwenje ndeye Raman kupararira.
Raman achipararira, zvakare, kupararira kweinelastic kwemwaranzi yemaziso pamamorekuru echinhu, iyo inoperekedzwa nekuchinja kukuru muhuwandu hwemwaranzi.
Nzira dzinoverengeka dzakashandiswa kusimbisa microstructural, thermal uye magetsi homogeneity yeheterostructures: scanning transmission electron microscopy (STEM), photoluminescence spectroscopy (PL), Kelvin probe microscopy (KPM), scanning thermal microscopy (SThM), pamwe neRaman spectroscopy uye. thermometry.
Image Image 1b inotiratidza Raman spectrum yeGr/MoSe2/MoS2/WSe22 heterostructure paSiO2/Si substrate panzvimbo yakanyorwa nedzvuku doti. Ichi chiitiko chinoratidza siginicha yega yega monolayer mune layer array, pamwe nekusaina kweSi substrate.
pamusoro 1c-1f rima-munda STEM mifananidzo yeGr/MoSe2/MoS2/WSe22 heterostructure inoratidzwa (1s) uye Gr/MoS2/WSe22 heterostructures (1d-1f) ine maredhisheni akasiyana. STEM mifananidzo inoratidza atomi yakavharika vdW gap pasina kusvibiswa, zvichibvumira kukora kwese kweaya heterostructures kuti anyatso kuoneka. Kuvapo kwekubatanidza kwemukati kwakasimbiswa zvakare pamusoro penzvimbo huru dzekuongorora uchishandisa photoluminescence (PL) spectroscopy (1g) Chiratidzo che photoluminescent chezvikamu zvakasiyana-siyana mukati meheterostructure inonyanya kudzvinyirirwa kana ichienzaniswa nechiratidzo chemonolayer yakazvimiririra. Izvi zvinotsanangurwa nemaitiro ekuchinjisa kuchaja nekuda kwekuvhara interlayer kupindirana, iyo inova yakanyanya kusimba mushure mekuvhara.
Mufananidzo #2
Kuti kuyere kupisa kuyerera perpendicular kune ndege dzeatomu dzeheterostructure, hurongwa hwematanho hwakagadzirwa nenzira yechina-probe magetsi emagetsi. Iyo yepamusoro graphene inobata palladium (Pd) maelectrodes uye inoshandiswa se hita yeRaman thermometry zviyero.
Iyi nzira yekudziya yemagetsi inopa chaiyo quantification yesimba rekupinza. Imwe nzira inobvira yekudziya, optical, ingave yakanyanya kuoma kuita nekuda kwekusaziva kweabsorption coefficients yezvikamu zvega.
pamusoro 2a inoratidza mana-probe kuyerwa dunhu, uye 2b inoratidza maonero epamusoro echimiro chiri kuedzwa. Purogiramu 2s inoratidza yakayerwa kupisa kupisa kwemidziyo mitatu, imwe ine graphene chete uye maviri ane Gr/WSe22 uye Gr/MoSe2/WSe22 layer arrays. Ese akasiyana anoratidza maitiro ambipolar egraphene, ayo ane chekuita nekusavapo kwebhendi gap.
Zvakaonekwa zvakare kuti ikozvino conduction uye kudziyisa kunoitika muupper layer (graphene), sezvo iwo magetsi conductivity ari akati wandei mirairo yehukuru kupfuura iyo yeMoS2 neWSe22.
Kuratidza homogeneity yemidziyo yakaedzwa, zviyero zvakatorwa pachishandiswa Kelvin probe microscopy (KPM) uye scanning thermal microscopy (SThM). Pachati 2d KPM zviyero zvinoratidzwa zvichiratidza mutsara unogona kugovera. Mhedzisiro yekuongorora kweSThM inoratidzwa mu 2s. Pano tinoona mepu yemagetsi anopisa Gr/MoS2/WSe22 chiteshi, pamwe nekuvapo kwekufanana mukupisa kwepamusoro.
Maitiro ekuvheneka anotsanangurwa pamusoro, kunyanya SThM, akasimbisa homogeneity yechimiro chiri pasi pechidzidzo, ndiko kuti, homogeneity yayo, maererano nekupisa. Nhanho yaitevera yaive yekuenzanisa tembiricha yeimwe neimwe yezvikamu zvemukati uchishandisa Raman spectroscopy (kureva, Raman spectroscopy).
Zvese zvitatu zvishandiso zvakaedzwa, imwe neimwe iine nzvimbo ye ~ 40 Β΅m2. Muchiitiko ichi, simba reheater rakashandurwa ne9 mW, uye iyo yakanyura laser simba yaive pazasi ~ 5 ΞΌW ine laser spot nzvimbo ~ 0.5 ΞΌm2.
Mufananidzo #3
Pachati 3a kuwedzera kwekushisa (βT) kwega yega yega uye substrate inoonekwa sezvo simba rekupisa muGr/MoS2/WSe22 heterostructure rinowedzera.
Materu emutsetse webasa rechinhu chimwe nechimwe (layer) anoratidza kupikisa kwemafuta (Rth = βT / P) pakati pegadziko rega uye sink yekupisa. Tichifunga nezve yunifomu yekugovera kupisa pamusoro penzvimbo, kupisa kwekupisa kunogona kuongororwa zviri nyore kubva pasi kusvika kumusoro, panguva iyo maitiro avo anogadziriswa nenzvimbo yechiteshi (WL).
L uye W ndiwo hurefu nehupamhi hwechiteshi, ayo akakura zvakanyanya kupfuura ukobvu hweSiO2 substrate uye lateral thermal kudziyisa kureba, inova ~ 0.1 ΞΌm.
Naizvozvo, isu tinokwanisa kutora iyo fomula yekupisa kwekupokana kweSi substrate, iyo ichaita seizvi:
Rth,Si β (WL)1/2 / (2kSi)
Mumamiriro ezvinhu aya kSi β 90 W mβ1 Kβ1, inova ndiyo inotarisirwa kudziya kwemhepo yepasireti ine doped yakanyanya.
Musiyano uripo pakati peRth,WSe2 neRth,Si ihuwandu hwekupikiswa kwekupisa kwe2 nm gobvu SiO100 uye iyo thermal boundary resistance (TBR) yeWSe2/SiO2 interface.
Kuisa zvese zviri pamusoro apa pamwechete, tinogona kuona kuti Rth,MoS2 β Rth,WSe2 = TBRMoS2/WSe2, uye Rth,Gr -Rth,MoS2 = TBRGr/MoS2. Naizvozvo, kubva pane girafu 3a zvinokwanisika kubvisa kukosha kweTBR kune imwe neimwe yeWSe2 / SiO2, MoS2 / WSe2 uye Gr / MoS2 interfaces.
Zvadaro, masayendisiti akafananidza kupikisa kwese kupisa kwese heterostructures, kuyerwa uchishandisa Raman spectroscopy uye thermal microscopy (3b).
Bilayer uye trilayer heterostructures paSiO2 yakaratidza kusimba kwekushisa kwe220 kusvika 280 m2 K/GW pakamuri yekushisa, iyo yakaenzana nekudzivirira kwekushisa kweSiO2 nekukora kwe290 kusvika 360 nm. Kunyangwe iyo iyo iyo ukobvu hweiyo heterostructures pasi pekudzidza haipfuure 2 nm (1d-1f), kupisa kwavo kunoitwa 0.007-0.009 W mβ1 K-1 pakupisa kwekamuri.
Mufananidzo #4
Mufananidzo 4 unoratidza kuyerwa kwezvimiro zvina zvese uye thermal boundary conductivity (TBC) yenzvimbo dzadzo, izvo zvinotibvumira kuongorora dhigirii reruremekedzo rwega rega pane yakamboyerwa kupisa kupisa (TBC = 1 / TBR).
Vatsvagiri vanocherekedza kuti iyi ndiyo yekutanga-yekutanga TBC kuyerwa kweatomu padhuze kupindirana pakati peakaparadzana monolayers (2D/2D), kunyanya pakati peWSe2 neSiO2 monolayers.
Iyo TBC yemonolayer WSe2/SiO2 interface yakadzikira pane yeakawanda WSe2/SiO2 interface, izvo hazvishamise sezvo iyo monolayer ine mashoma mashoma ekubhenda phonon modes anowanikwa kutapurirana. Zvichitaurwa zviri nyore, iyo TBC yekubatana pakati pe2D layer yakadzikira pane TBC yemusanganiswa pakati peiyo 2D layer uye 3D SiO2 substrate (4b).
Kuti uwane rumwe ruzivo rwakadzama rwema nuances echidzidzo, ini ndinokurudzira kutarisa ΠΈ kwaari.
Epilogue
Tsvagiridzo iyi, sekutaura kunoita vesainzi pachavo, inotipa ruzivo runogona kushandiswa mukuitwa kweatomu yekupisa kupindirana. Iri basa rakaratidza mukana wekugadzira kupisa-insulating metamaterials ayo maitiro asingawanikwe mune zvakasikwa. Pamusoro pezvo, chidzidzo ichi chakasimbisawo mukana wekuita zviyero zvetembiricha zvezvimiro zvakadaro, zvisinei nechiyero cheatomu chezvikamu.
Heterostructures inotsanangurwa pamusoro apa inogona kuva nheyo ye-ultra-light uye compact thermal "shields", inokwanisa, semuenzaniso, kubvisa kupisa kubva munzvimbo dzinopisa mumagetsi. Uye zvakare, tekinoroji iyi inogona kushandiswa mune thermoelectric jenareta kana zvigadziriso zvinodzorwa nemhepo, zvichiwedzera kuita kwavo.
Ichi chidzidzo chinosimbisa zvakare kuti sainzi yemazuva ano inofarira zvakakomba musimboti we "kubudirira mune thimble," iyo isingagoni kunzi pfungwa yeupenzi, zvichipiwa zviwanikwa zvishoma zvepasi uye kukura kunoenderera mukudiwa kwemarudzi ese ehunyanzvi hwekuvandudza tekinoroji.
Ndatenda nekuverenga, garai muchida kuziva uye muve nevhiki yakanaka vakomana! π
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Source: www.habr.com