He nui nā mea pāʻani a puni ka honua i ʻike i ka wā Xbox 360 i kamaʻāina loa i ke kūlana i ka wā i lilo ai kā lākou console i pā palai kahi e hiki ai iā lākou ke ʻai i nā hua. ʻAʻole hiki ke ʻano kaumaha like me nā consoles pāʻani, akā me nā kelepona, laptops, papa a me nā mea hou aku. Ma ke kumu, aneane hiki i nā mea uila ke ʻike i ka haʻalulu wela, ʻaʻole hiki ke alakaʻi wale i kona hāʻule ʻole a me ka huhū o ka mea nona, akā i ka "boom maikaʻi ʻole" o ka pākaukau a me ka hōʻeha koʻikoʻi. I kēia lā, e kamaʻāina mākou i kahi haʻawina i hana ai nā ʻepekema mai ke Kulanui ʻo Stanford, e like me Nick Fury mai ka comics, i kahi pale e pale ai i nā ʻāpana uila i ka wela mai ka wela a ma muli o ka hopena, pale i ko lākou haki. Pehea ka hana ʻana o nā ʻepekema i kahi pale wela, he aha kāna mau mea nui a pehea ka maikaʻi? Aʻo mākou e pili ana i kēia a me nā mea hou aʻe mai ka hōʻike a ka hui noiʻi. Hele.
Kumu noiʻi
Ua ʻike ʻia ka pilikia o ka overheating no ka manawa lōʻihi, a ua hoʻoponopono nā ʻepekema i nā ʻano like ʻole. ʻO kekahi o nā mea kaulana loa ka hoʻohana ʻana i ke aniani, ka plastic a me nā ʻāpana o ka ea, e lawelawe ana ma ke ʻano he insulators o ka radiation thermal. I nā ʻano ʻoiaʻiʻo o kēia wā, hiki ke hoʻomaikaʻi ʻia kēia ʻano hana ma ka hoʻemi ʻana i ka mānoanoa o ka papa pale i kekahi mau atom me ka ʻole o ka nalowale ʻana o kāna mau waiwai insulation thermal. ʻO ia ka mea a nā mea noiʻi i hana ai.
Ke kamaʻilio nei mākou e pili ana i nā nanomaterials. Eia nō naʻe, ua paʻakikī ko lākou hoʻohana ʻana i ka insulation thermal ma mua o ka ʻoiaʻiʻo o ka lōʻihi o ka nalu o nā mea hoʻoluʻu (nā kelepona *) ʻoi aku ka pōkole ma mua o nā electrons a i ʻole photons.
Phonon* - he quasiparticle, ʻo ia ka quantum o ka neʻe vibrational o nā ʻātoma aniani.
Eia kekahi, ma muli o ke ʻano bosonic o nā phonons, ʻaʻole hiki ke hoʻomalu iā lākou e ka uila (e like me ka hana ʻana me nā mea lawe ukana), ʻo ia ka mea paʻakikī ke kāohi i ka hoʻoili ʻana o ka wela i nā mea paʻa.
Ma mua, ua hoʻomalu ʻia nā waiwai wela o nā mea paʻa, e like me ka poʻe noiʻi e hoʻomanaʻo mai iā mākou, ma o nā kiʻiʻoniʻoni nanolaminate a me nā superlattices ma muli o ka maʻi kino a me nā pilina kiʻekiʻe kiʻekiʻe, a i ʻole ma o nā nanowires silicon a me germanium ma muli o ka hoʻopuehu phonon ikaika.
I kekahi mau ʻano hana insulation thermal i hōʻike ʻia ma luna, ua mākaukau nā ʻepekema e hoʻopili i nā mea ʻelua-dimensional, ʻo ka mānoanoa o ia mea ʻaʻole i ʻoi aku ma mua o ka nui o nā atoms, e maʻalahi lākou e hoʻokele ma kahi pālākiō atomika. I kā lākou aʻo ʻana ua hoʻohana lākou van der Waals (vdW) ka hui ʻana o nā ʻāpana 2D lahilahi atomically e hoʻokō i ke kūpaʻa wela kiʻekiʻe loa i ko lākou heterostructure.
Nā pūʻali koa Van der Waals* — nā pūʻali hoʻopili intermolecular/interatomic me ka ikehu o 10-20 kJ/mol.
ʻO ka ʻenehana hou i hiki ai ke loaʻa ke kūpaʻa wela i loko o kahi 2 nm mānoanoa vdW heterostructure i hoʻohālikelike ʻia me ka 2 nm mānoanoa SiO300 (silicon dioxide).
Eia kekahi, ua hiki i ka hoʻohana ʻana i nā heterostructures vdW ke loaʻa ka mana ma luna o nā waiwai wela ma ka pae atomic ma o ka hoʻopaʻa ʻana o nā monolayers heterogenous XNUMXD me nā ʻano nui atomic like ʻole a me nā ʻano vibrational.
No laila, mai huki kākou i ka ʻumiʻumi o ka pōpoki a hoʻomaka kākou e noʻonoʻo i nā hopena o kēia noiʻi kupaianaha.
Nā hopena noiʻi
ʻO ka mea mua, e kamaʻāina kākou i nā hiʻohiʻona microstructural a me nā hiʻohiʻona o nā heterostructure vdW i hoʻohana ʻia i kēia haʻawina.
Kiʻi #1
Ma ke kiʻi 1 hōʻike i ke kiʻikuʻi cross-sectional o kahi heterostructure ʻehā-papa ʻo (mai luna a lalo): graphene (Gr), MoSe2, MoS2, WSe22 a me kahi substrate SiO2/Si. No ka nānā 'ana i nā papa a pau i ka manawa like, e ho'ohana Raman laser* me ka loa hawewe o 532 nm.
Raman laser* - he ʻano laser kahi i hoʻopuʻi ʻia ai ʻo Raman ka mīkini nui o ka hoʻonui ʻana i ka māmā.
Hoʻopuehu ʻo Raman, ʻo ia hoʻi ka hoʻopuehu ʻole ʻana o ka radiation optical ma nā molekala o kahi mea, i hui pū ʻia me ka hoʻololi nui i ka pinepine o ka radiation.
Ua hoʻohana ʻia kekahi mau ʻano e hōʻoia i ka homogeneity microstructural, thermal a me uila o heterostructures: scanning transmission electron microscopy (STEM), photoluminescence spectroscopy (PL), Kelvin probe microscopy (KPM), scanning thermal microscopy (SThM), a me Raman spectroscopy a thermometry .
Kiʻi 1b hōʻike iā mākou i ke kikoʻī Raman o kahi Gr / MoSe2 / MoS2 / WSe22 heterostructure ma kahi substrate SiO2 / Si ma kahi i kaha ʻia me kahi kiko ʻulaʻula. Hōʻike kēia ʻāpana i ka pūlima o kēlā me kēia monolayer i ka papa papa, a me ka pūlima o ka substrate Si.
maluna o 1c-1f Hōʻike ʻia nā kiʻi STEM o ka Gr/MoSe2/MoS2/WSe22 heterostructure (1c) a me Gr/MoS2/WSe22 heterostructures (1d-1f) me nā ʻano lattice ʻokoʻa. Hōʻike nā kiʻi STEM i nā āpau vdW kokoke loa me ka ʻole o ka haumia, e ʻae i ka mānoanoa holoʻokoʻa o kēia mau heterostructure e ʻike pono ʻia. Ua hōʻoia pū ʻia ka hele ʻana o ka hui interlayer ma luna o nā wahi scanning nui me ka hoʻohana ʻana i ka photoluminescence (PL) spectroscopy (1g). ʻO ka hōʻailona photoluminescent o nā papa hoʻokahi i loko o ka heterostructure ua kāohi nui ʻia i ka hoʻohālikelike ʻana i ka hōʻailona o kahi monolayer kaʻawale. Ua wehewehe ʻia kēia e ke kaʻina o ka hoʻoili ʻana i ka uku interlayer ma muli o ka pilina pili interlayer, a ʻoi aku ka ikaika ma hope o ka annealing.
Kiʻi #2
I mea e ana i ke kahe wela e pili pono ana i na mokulele atomika o ka heterostructure, ua kukuluia ka papa o na papa ma ke ano o na mea uila eha-probe. ʻO ka papa luna o ka graphene contact palladium (Pd) electrodes a hoʻohana ʻia ma ke ʻano he mea hoʻomehana no nā ana thermometry Raman.
Hāʻawi kēia ʻano hoʻomehana uila i ka helu pololei o ka mana hoʻokomo. ʻOi aku ka paʻakikī o ka hoʻokō ʻana ma muli o ka ʻike ʻole o nā coefficient absorption o kēlā me kēia papa.
maluna o 2 hōʻike i kahi kaapuni ana ʻehā, a 2b hōʻike i kahi ʻike kiʻekiʻe o ka hale e hoʻāʻo ʻia nei. Papa kuhikuhi 2c hōʻike i nā hiʻohiʻona hoʻoili wela i ana ʻia no ʻekolu mau mea hana, hoʻokahi i loaʻa i ka graphene wale nō a ʻelua i loko o nā papa papa Gr/WSe22 a me Gr/MoSe2/WSe22. Hōʻike nā ʻano ʻokoʻa āpau i ke ʻano ambipolar o ka graphene, e pili ana me ka nele o kahi ʻāpana.
Ua ʻike pū ʻia ka hana ʻana a me ka hoʻomehana i kēia manawa ma ka papa luna (graphene), no ka mea, ʻoi aku ka nui o kāna conductivity uila ma mua o ka MoS2 a me WSe22.
No ka hōʻike ʻana i ka homogeneity o nā mea i hoʻāʻo ʻia, ua lawe ʻia nā ana me ka hoʻohana ʻana i ka microscopy Kelvin probe (KPM) a me ka scanning thermal microscopy (SThM). Ma ka pakuhi 2d Hōʻike ʻia nā ana KPM e hōʻike ana i ka hoʻohele laina laina. Hōʻike ʻia nā hopena o ka hōʻike SThM ma 2s. Maʻaneʻi mākou eʻike ai i ka palapala 'āina o nā kaha Gr / MoS2 / WSe22 i hoʻomehanaʻia i ka uila, a me ka heleʻana o ka likeʻole i ka hoʻomehana honua.
ʻO nā ʻenehana scanning i hōʻike ʻia ma luna, ma kahi SThM, ua hōʻoia i ka homogeneity o ka hale e aʻo ʻia, ʻo ia hoʻi, kona homogeneity, ma ke ʻano o nā mahana. ʻO ka ʻanuʻu aʻe, ʻo ia ka helu ʻana i ka mahana o kēlā me kēia o nā papa hana me ka hoʻohana ʻana i ka spectroscopy Raman (ʻo ia hoʻi, Raman spectroscopy).
Ua hoʻāʻo ʻia nā mea hana ʻekolu, kēlā me kēia me kahi wahi o ~ 40 µm2. I kēia hihia, ua hoʻololi ʻia ka mana wela e 9 mW, a ʻo ka mana laser i hoʻopaʻa ʻia ma lalo o ~5 μW me kahi wahi wahi laser o ~0.5 μm2.
Kiʻi #3
Ma ka pakuhi 3 ʻike ʻia ka piʻi ʻana o ka mahana (∆T) o kēlā me kēia papa a me ka substrate i ka piʻi ʻana o ka mana wela i ka Gr/MoS2/WSe22 heterostructure.
Hōʻike nā pali o ka hana laina no kēlā me kēia mea (layer) i ke kū'ē wela (Rth=∆T/P) ma waena o kēlā me kēia papa a me ka wela wela. Hāʻawi ʻia i ka hāʻawi like ʻana o ka hoʻomehana ʻana ma luna o ka wahi, hiki ke maʻalahi i ka nānā ʻana i nā kūʻē wela mai ka lalo a i ka papa luna, kahi i hoʻohālikelike ʻia ko lākou mau waiwai e ka wahi kahawai (WL).
ʻO L a me W ka lōʻihi a me ka laula o ke kahawai, ʻoi aku ka nui ma mua o ka mānoanoa o ka substrate SiO2 a me ka lōʻihi wela wela o ka ʻaoʻao, ʻo ia ka ~ 0.1 μm.
No laila, hiki iā mākou ke kiʻi i ke ʻano no ke kūpaʻa wela o ka substrate Si, e like me kēia:
Rth,Si ≈ (WL)1/2 / (2kʻo)
Ma keia kulana kʻO Si ≈ 90 W m−1 K−1, ʻo ia ka mea i manaʻo ʻia ka hoʻoili wela o ia substrate doped loa.
ʻO ka ʻokoʻa ma waena o Rth, WSe2 a me Rth, Si ka huina o ke kūpaʻa wela o 2 nm mānoanoa SiO100 a me ke kūpaʻa palena wela (TBR) o ka interface WSe2/SiO2.
I ka hui pū ʻana i nā mea a pau i luna, hiki iā mākou ke hoʻokumu i kēlā Rth,MoS2 − Rth,WSe2 = TBRMoS2/WSe2, a me Rth,Gr - Rth,MoS2 = TBRGr/MoS2. No laila, mai ka pakuhi 3 hiki ke unuhi i ka waiwai TBR no kēlā me kēia o nā pilina WSe2 / SiO2, MoS2 / WSe2 a me Gr / MoS2.
A laila, ua hoʻohālikelike ka poʻe ʻepekema i ka nui o ke kūpaʻa wela o nā heterostructure āpau, ana ʻia me ka Raman spectroscopy a me ka thermal microscopy (3b).
ʻO ka Bilayer a me ka trilayer heterostructures ma SiO2 hōʻike i ke kū'ē wela maikaʻi ma ka laulā o 220 a 280 m2 K / GW ma ke ana wela, ua like ia me ka pale wela o SiO2 me ka mānoanoa o 290 a 360 nm. ʻOiai ʻo ka mānoanoa o nā heterostructure ma lalo o ke aʻo ʻana ʻaʻole i ʻoi aku ma mua o 2 nm (1d-1f), 0.007-0.009 W m−1 K−1 ko lakou maa wela ma ka lumi wela.
Kiʻi #4
Hōʻike ke kiʻi 4 i nā ana o nā hale ʻehā a me ka conductivity palena wela (TBC) o kā lākou mau pilina, e hiki ai iā mākou ke loiloi i ke kiʻekiʻe o ka mana o kēlā me kēia papa ma luna o ke kūpaʻa wela i ana mua ʻia (TBC = 1 / TBR).
Hoʻomaopopo ka poʻe noiʻi ʻo kēia ke ana TBC mua loa no nā pilina pili atomically ma waena o nā monolayers kaʻawale (2D/2D), ma waena o WSe2 a me SiO2 monolayers.
ʻOi aku ka haʻahaʻa o ka TBC o kahi interface WSe2/SiO2 monolayer ma mua o ka interface multilayer WSe2/SiO2, ʻaʻole ia he mea kupanaha no ka mea ʻoi aku ka liʻiliʻi o ka monolayer i nā mode phonon bending i loaʻa no ka hoʻouna ʻana. ʻO ka waiho wale ʻana, ʻoi aku ka haʻahaʻa o ka TBC o ka pilina ma waena o nā papa 2D ma mua o ka TBC o ke kikowaena ma waena o ka papa 2D a me ka substrate 3D SiO2 (4b).
No ka ʻike kikoʻī hou aku me nā nuances o ke aʻo ʻana, manaʻo wau e nānā и iāia.
Epilogue
ʻO kēia noiʻi, e like me ka ʻōlelo a ka poʻe ʻepekema ponoʻī, hāʻawi iā mākou i ka ʻike e hiki ke hoʻohana ʻia i ka hoʻokō ʻana i nā pilina wela atomic. Ua hōʻike kēia hana i ka hiki ke hana i nā metamaterial hoʻokaʻawale wela nona nā waiwai i ʻike ʻole ʻia ma ke ʻano. Eia kekahi, ua hōʻoia ka haʻawina i ka hiki ke hoʻokō i nā ana wela kūpono o ia mau hale, ʻoiai ke ʻano atomic o nā papa.
Hiki i nā heterostructure i ho'ākākaʻia ma luna nei ke kumu no ka ultra-light a me ka compact thermal "pale", hiki, no ka laʻana, ke wehe i ka wela mai nā wahi wela i ka uila. Eia kekahi, hiki ke hoʻohana ʻia kēia ʻenehana i nā mea hana thermoelectric a i ʻole nā mea hoʻomalu thermally, e hoʻonui ana i kā lākou hana.
Ke hōʻoia hou nei kēia haʻawina e makemake nui ka ʻepekema hou i ke kumu o ka "kūpono i ka thimble," ʻaʻole hiki ke kapa ʻia he manaʻo naʻaupō, hāʻawi ʻia i nā kumuwaiwai liʻiliʻi o ka honua a me ka ulu mau o ka noi no nā ʻano hana ʻenehana āpau.
Mahalo iā ʻoe no kou nānā ʻana, noho ʻimi a hauʻoli maikaʻi i kēlā me kēia pule! 🙂
Mahalo no kou noho pū ʻana me mākou. Makemake ʻoe i kā mākou ʻatikala? Makemake ʻoe e ʻike i nā mea hoihoi hou aʻe? E kākoʻo iā mākou ma ke kau ʻana i kahi kauoha a i ʻole ka ʻōlelo ʻana i nā hoaaloha, 30% ho'ēmi no nā mea hoʻohana Habr ma kahi kūʻokoʻa kūʻokoʻa o nā kikowaena helu komo, i hana ʻia e mākou no ʻoe: (loaʻa me RAID1 a me RAID10, a hiki i 24 cores a hiki i 40GB DDR4).
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Source: www.habr.com