“ʻO Mutation ke kī e wehe ai i ka mea pohihihi o ka evolution. ʻO ke ala o ka hoʻomohala ʻana mai ka mea ola maʻalahi a hiki i nā ʻano mea ola koʻikoʻi he mau kaukani makahiki. Akā, i kēlā me kēia haneli kaukani makahiki, aia kahi lele nui i mua o ka evolution" (Charles Xavier, X-Men, 2000). Inā mākou e hoʻolei i nā mea ʻepekema-fiction a pau i loaʻa i nā comics a me nā kiʻiʻoniʻoni, a laila he ʻoiaʻiʻo nā ʻōlelo a Profesor X. ʻO ka hoʻomohala ʻana o kekahi mea e hele like i ka hapa nui o ka manawa, akā i kekahi manawa aia nā lele i loaʻa ka hopena nui i ke kaʻina holoʻokoʻa. ʻAʻole pili kēia i ka hoʻomohala ʻana o nā ʻano, akā i ka evolution o ka ʻenehana, ʻo ka mea hoʻokele nui o ka poʻe, kā lākou noiʻi a me nā mea i hana ʻia. I kēia lā, e kamaʻāina mākou i kahi noiʻi, e like me kāna mea kākau, he lele hoʻololi maoli i ka nanotechnology. Pehea i hana ai nā ʻepekema mai Northwestern University (USA) i ka hana ʻana i kahi heterostructure ʻelua-dimensional hou, no ke aha i koho ʻia ai ka graphene a me ka borophene i kumu, a he aha nā waiwai i loaʻa i ia ʻōnaehana? ʻO ka hōʻike o ka hui noiʻi e haʻi iā mākou e pili ana i kēia. Hele.
Kumu noiʻi
Ua lohe pinepine mākou i ka huaʻōlelo "graphene", he hoʻololi ʻelua ʻāpana o ke kalapona, ʻo ia ka papa o nā ʻātoma kalapona 1 atom mānoanoa. Akā ʻaʻole kakaikahi ka "borofen". ʻO kēia huaʻōlelo e pili ana i kahi aniani ʻelua-dimensional i loaʻa i nā ʻātoma boron (B) wale nō. Ua wānana mua ʻia ka hiki ʻana o ka borophene i ka waena o 90s, akā i ka hoʻomaʻamaʻa ʻana ua loaʻa kēia hale i ka makahiki 2015.
ʻO ka hoʻolālā atomika o ka borophene he mau mea triangular a hexagonal a he hopena ia o ka pilina ma waena o ʻelua-waena a me multi-center in-plane bond, he mea maʻamau no nā mea electron-deficient, ʻo ia hoʻi ka boron.
*ʻO nā paʻa ʻelua-waena a me multicenter ke manaʻo nei mākou i nā paʻa kemika - nā pilina o nā mana e hōʻike ana i ke kūpaʻa o kahi mole a i ʻole ke aniani ma ke ʻano he hale hoʻokahi. No ka laʻana, loaʻa kahi paʻa ʻelua-kelepona ʻelua i ka wā e hoʻokaʻawale ai nā ʻātoma 2 i nā electrons 2, a loaʻa kahi paʻa ʻekolu-electron ʻelua-waena ke loaʻa nā 2 atom a me 3 electrons, etc.
Mai ka ʻike kino, ʻoi aku ka ikaika a ʻoi aku ka maʻalahi o ka borophene ma mua o ka graphene. Manaʻo ʻia ʻo nā hale borophene hiki ke lilo i mea hoʻokō pono no nā pākaukau no ka mea he kiʻekiʻe ka mana kikoʻī a me ka conductivity uila kūikawā a me nā waiwai lawe ion. Eia naʻe, i kēia manawa he manaʻo wale nō kēia.
Ke noho nei mea ʻekolu *, he 10 paha ka boron alotrope*. Ma ke ʻano ʻelua-dimensional, like polymorphism* nānā ʻia nō hoʻi.
ʻElemu trivalent* hiki iā ia ke hana i ʻekolu mau mea hoʻopaʻa covalent, ʻo ia ka valency ʻekolu.
Allotropy* - inā hiki ke hōʻike ʻia hoʻokahi mea kemika ma ke ʻano o ʻelua mau mea maʻalahi. E like me ka laʻana, carbon - daimana, graphene, graphite, carbon nanotubes, etc.
Polymorphism* - ka hiki o kahi mea ke noho i loko o nā hale aniani like ʻole (polymorphic modifications). I ka hihia o nā mea maʻalahi, ua like kēia huaʻōlelo me ka allotropy.
Hāʻawi ʻia kēia polymorphism ākea, manaʻo ʻia he moho maikaʻi loa ka borophene no ka hana ʻana i nā heterostructure ʻelua-dimensional hou, no ka mea, ʻo nā hoʻonohonoho hoʻopaʻa boron ʻokoʻa e hoʻomaha i nā koi hoʻohālikelike. ʻO ka mea pōʻino, ua aʻo mua ʻia kēia pilikia ma ka pae theoretical ma muli o nā pilikia i ka synthesis.
No nā mea 2D maʻamau i loaʻa mai nā kristal ʻāpana nui, hiki ke hoʻokō ʻia nā heterostructure kūwaho me ka hoʻohana ʻana i ka mechanical stacking. Ma ka ʻaoʻao ʻē aʻe, hoʻokumu ʻia nā heterostructure ʻaoʻao ʻelua i ka synthesis lalo. Hiki i nā heterostructure ʻaoʻao atomically pololei i ka hoʻonā ʻana i nā pilikia hoʻokele hana heterojunction, akā naʻe, ma muli o ka hoʻopaʻa ʻana i ka covalent, ʻo ka hoʻohālikelike ʻana i ka lattice maikaʻi ʻole i ka hopena maʻamau i nā pilina ākea a huikau. No laila, hiki ke loaʻa, akā aia kekahi pilikia i ka hoʻokō ʻana.
Ma kēia hana, ua hiki i nā mea noiʻi ke hoʻohui i ka borophene a me ka graphene i hoʻokahi heterostructure ʻelua-dimensional. ʻOiai ka like ʻole o ka lattice crystallographic a me ka hoʻohālikelike ma waena o ka borophene a me ka graphene, ka waiho ʻana o ke kalapona a me ka boron ma luna o kahi substrate Ag (111) ma lalo o ka ʻūhā kiʻekiʻe kiʻekiʻe (UHV) ka hopena i nā heterointerfaces ʻaoʻao atomically pololei me nā alignment lattice wānana, a me nā heterointerfaces vertical. .
Nā hoʻomākaukau no ka noi
Ma mua o ke aʻo ʻana i ka heterostructure, pono e hana ʻia. ʻO ka ulu ʻana o ka graphene a me ka borophene i lawe ʻia i loko o kahi keʻena ʻeleʻele ultra-high me ke kaomi o 1x10-10 millibars.
Ua hoʻomaʻemaʻe ʻia ka substrate crystal Ag(111) hoʻokahi e nā pōʻai pinepine o Ar+ sputtering (1 x 10-5 millibar, 800 eV, 30 mau minuke) a me ka hoʻoheheʻe wela (550 °C, 45 mau minuke) e loaʻa i kahi Ag (111 °C, XNUMX mau minuke) i hoʻomaʻemaʻe ʻia. XNUMX) ʻili.
Ua ulu ʻia ʻo Graphene e ka electron beam evaporation o kahi koʻokoʻo graphite maʻemaʻe (99,997%) me ke anawaena o 2.0 mm ma luna o kahi substrate Ag (750) i hoʻomehana ʻia i 111 °C ma kahi manawa hoʻomehana o ~ 1.6 A a me kahi voli wikiwiki o ~ 2 kV. , e hāʻawi ana i kahi manawa hoʻokuʻu o ~ 70 mA a me ke kalapona kalapona ~ 40 nA. ʻO ke kaomi i loko o ke keʻena he 1 x 10-9 millibars.
Ua ulu ʻia ka Borophene ma o ka hoʻoheheʻe ʻia ʻana o ke kukui uila o kahi koʻokoʻo boron maʻemaʻe (99,9999%) ma luna o ka submonolayer graphene ma Ag (400) i hoʻomehana ʻia i 500-111 °C. ʻO ka filament o kēia manawa he ~ 1.5 A a ʻo ka uila wikiwiki ʻo 1.75 kV, e hāʻawi ana i kahi manawa hoʻokuʻu o ~34 mA a me kahi kahe boron o ~10 nA. ʻO ke kaomi i loko o ke keʻena i ka wā o ka ulu ʻana o ka borophene ma kahi o 2 x 10-10 millibars.
Nā hopena noiʻi
Kiʻi #1
Ma ke kiʻi 1A i hōʻike ʻia STM* he paʻi kiʻi o ka graphene ulu, kahi e ʻike maikaʻi ʻia ai nā kāʻei graphene me ka palapala ʻāina dI/dV (1B), kahi I и V ʻo ia ke au o ka tunneling a me ka neʻe ʻana o ka hāpana, a d - mānoanoa.
STM* - ka nānā ʻana i ka microscope tunneling.
dI/dV ʻO nā palapala 'āina o ka laʻana i ʻae iā mākou e ʻike i kahi kiʻekiʻe kūloko kūloko o nā mokuʻāina o graphene i hoʻohālikelike ʻia me ka substrate Ag (111). E like me nā haʻawina mua, ʻo ka mokuʻāina ʻo Ag (111) he ʻano ʻanuʻu, ua neʻe ʻia i ka ikaika maikaʻi e dI/dV spectrum of graphene (1С), e wehewehe ana i ke kiʻekiʻe o nā mokuʻāina o graphene ma 1B ma 0.3 eV.
Ma ke kiʻi 1D hiki iā mākou ke ʻike i ke ʻano o ka graphene one-layer, kahi o ka honeycomb lattice a moiré superstructure*.
ʻO ke kūkulu ʻana * - kahi hiʻohiʻona o ke ʻano o kahi hui crystalline e hana hou ana i kekahi manawa a pēlā e hana ai i kahi hale hou me kahi manawa hoʻololi ʻē aʻe.
Moire* - ka hoʻonohonoho ʻana o ʻelua mau hiʻohiʻona mesh manawa ma luna o kekahi.
Ma nā haʻahaʻa haʻahaʻa, ulu ka ulu i ka hoʻokumu ʻana i nā domain dendritic a me nā graphene defect. Ma muli o ka nawaliwali o ka pilina ma waena o ka graphene a me ka substrate lalo, ʻaʻole kū hoʻokahi ka hoʻololi ʻana o ka graphene e pili ana i ka Ag(111).
Ma hope o ka waiho ʻana o ka boron, e nānā ana i ka microscopy tunneling (1E) ua hōʻike i ka hiki ʻana mai o kahi hui o borophene a me graphene domain. ʻIke ʻia ma ke kiʻi nā ʻāpana i loko o ka graphene, i ʻike ʻia ma hope he graphene i hoʻopili ʻia me ka borophene (i hōʻike ʻia ma ke kiʻi. Gr/B). ʻO nā mea laina laina i kuhikuhi ʻia i ʻekolu ʻaoʻao a hoʻokaʻawale ʻia e kahi kihi o 120 ° ke ʻike maopopo ʻia ma kēia wahi (nā pua melemele).
Kiʻi #2
Kiʻi ma 2Aaoiaʻe 1E, hōʻoia i ka ʻike ʻia ʻana o nā pōʻeleʻele kūloko i ka graphene ma hope o ka waiho ʻana o ka boron.
I mea e nānā pono ai i kēia mau hoʻokumu ʻana a ʻike i ko lākou kumu, ua kiʻi ʻia kekahi kiʻi ʻē aʻe o ia wahi like, akā me ka hoʻohana ʻana i nā palapala |dlnI/dz| (2B), kahi I — ke au ala ala, d ʻo ka mānoanoa, a z - ka hoʻokaʻawale ʻana o ka probe-sample (ke āpau ma waena o ka nila microscope a me ka hāpana). ʻO ka hoʻohana ʻana i kēia ʻenehana hiki ke loaʻa nā kiʻi me ka hoʻonā kiʻekiʻe spatial. Hiki iā ʻoe ke hoʻohana i ka CO a i ʻole H2 ma ka nila microscope no kēia.
Kiʻi 2С he kiʻi i loaʻa me ka STM nona ka piko i uhi ʻia me CO. Ka hoohalike ana o na kii А, В и С hōʻike ʻia ua wehewehe ʻia nā mea atomika āpau he ʻekolu hexagons ʻālohilohi pili i kuhikuhi ʻia i ʻelua ʻaoʻao like ʻole (nā huinakolu ʻulaʻula a melemele i nā kiʻi).
Nā kiʻi i hoʻonui ʻia o kēia wahi (2D) e hōʻoiaʻiʻo ua ʻaelike kēia mau mea me nā haumia boron dopant, e noho ana i ʻelua sublattices graphene, e like me ka mea i hōʻike ʻia e nā hale superimposed.
ʻO ka uhi CO o ka nila microscope i hiki ke hōʻike i ke ʻano geometric o ka pepa borophene (2E), he mea hiki ʻole inā he maʻamau ka nila (metala) me ka uhi ʻole CO.
Kiʻi #3
Ka hoʻokumu ʻana o nā ʻaoʻao heterointerfaces ma waena o borophene a me graphene (3A) i ka wā e ulu ai ka borophene e pili ana i nā kāʻei kapu graphene i loaʻa i ka boron.
Hoʻomanaʻo ka poʻe ʻepekema ʻo nā ʻaoʻao heterointerfaces e pili ana i ka graphene-hBN (graphene + boron nitride) loaʻa ka lattice kūlike, a ʻo nā heterojunctions e pili ana i ka transition metal dichalcogenides he symmetry consistency. I ka hihia o ka graphene/borophene, ʻokoʻa iki ke kūlana - he liʻiliʻi ko lākou ʻano like ʻole e pili ana i nā lattice mau a i ʻole symmetry aniani. Eia nō naʻe, me kēia, hōʻike ka lateral graphene/borophene heterointerface i ke ʻano like ʻole o ka atomic, me ka laina boron (B-laina) kuhikuhi i nā kuhikuhi zigzag (ZZ) o graphene (3A). Ma 3B Hōʻike ʻia kahi kiʻi i hoʻonui ʻia o ka ʻāpana ZZ o ka heterointerface (hōʻike nā laina uliuli i nā mea kikowaena pili e pili ana i nā paʻa covalent boron-carbon).
Ma muli o ka ulu ʻana o ka borophene ma kahi haʻahaʻa haʻahaʻa e hoʻohālikelike ʻia me ka graphene, ʻaʻole hiki ke loaʻa ka mobility kiʻekiʻe o nā kihi o ka domain graphene i ka wā e hana ai i kahi heterointerface me borophene. No laila, ʻo ka heterointerface kokoke i atomically pololei paha he hopena o nā hoʻonohonoho like ʻole a me nā hiʻohiʻona o nā paʻa boron multisite. Ka nānā 'ana i nā kiko kiko'ī o ka tunneling spectroscopy (3С) a me ka hoʻokahe ʻana o ka tunnel ʻokoʻa (3D) hōʻike i ka hoʻololi uila mai ka graphene a hiki i ka borophene ma kahi mamao o ~5 Å me ka ʻike ʻole ʻia o nā mokuʻāina.
Ma ke kiʻi 3E Hōʻike ʻia ʻekolu hiʻohiʻona hiʻohiʻona hoʻoheheʻe tunneling i lawe ʻia ma nā laina kīwī ʻekolu ma 3D, e hōʻoia ana he mea ʻole kēia hoʻololi uila pōkole i nā hale kikowaena kūloko a ua hoʻohālikelike ʻia me nā borophene-silver interface.
Kiʻi #4
Graphene intercalation* ua aʻo nui ʻia ma mua, akā kakaikahi ka hoʻololi ʻana o nā intercalants i nā pepa 2D maoli.
Intercalation* - hiki ke hoʻohuli ʻia ka hoʻokomo ʻana o kahi mole a i ʻole pūʻulu o nā molekole ma waena o nā molekala a i ʻole nā hui o nā mole.
ʻO ka radius atomika liʻiliʻi o ka boron a me ka pilina nāwaliwali ma waena o ka graphene a me Ag(111) e hōʻike ana i ka intercalation o ka graphene me ka boron. Ma ke kiʻi 4A Hōʻike ʻia nā hōʻike ʻaʻole wale no ka intercalation boron, akā no ka hoʻokumu ʻana i nā heterostructures vertical borophene-graphene heterostructures, ʻoi aku ka nui o nā domain triangular i hoʻopuni ʻia e ka graphene. ʻO ka lattice honeycomb i ʻike ʻia ma kēia ʻāpana triangular e hōʻoia i ka hele ʻana o ka graphene. Eia naʻe, hōʻike kēia graphene i kahi haʻahaʻa haʻahaʻa o nā mokuʻāina ma -50 meV i hoʻohālikelike ʻia me ka graphene a puni (4B). Ke hoʻohālikelike ʻia me ka graphene ma luna o Ag(111), ʻaʻohe mea hōʻike no ke kiʻekiʻe kiʻekiʻe o nā mokuʻāina i ka spectrum. dI/dV (4C, ka polū polū), pili i ka Ag(111) moku'āina ili, 'o ia ka hō'ike mua o ka boron intercalation.
Eia kekahi, e like me ka mea i manaʻo ʻia no ka intercalation hapa, e mau ana ka lattice graphene ma ka ʻaoʻao ʻaoʻao ma waena o ka graphene a me ka ʻāpana triangular (4D - pili i kahi ʻāpana ʻehā ma 4A, hoʻopuni ʻia i ka laina kiko ʻulaʻula). Ua hōʻoia pū kekahi kiʻi e hoʻohana ana i ka CO ma kahi nila microscope i ka loaʻa ʻana o nā haumia pani pani boron (4E - pili i kahi ʻāpana ʻehā ma 4A, puni i ka laina kiko melemele).
Ua hoʻohana pū ʻia nā nila microscope me ka uhi ʻole ʻia i ka wā o ka nānā ʻana. I kēia hihia, ua hōʻike ʻia nā hōʻailona o nā mea laina laina hoʻokahi me ka periodicity o 5 Å i nā kikowaena graphene intercalated (4F и 4G). Ua like kēia mau hana hoʻokahi me nā lālani boron i loko o ke kumu hoʻohālike borophene. Ma waho aʻe o ka hoʻonohonoho o nā kiko e pili ana i ka graphene, ka hoʻololi ʻana o Fourier o ke kiʻi i 4G hōʻike i ʻelua mau kiko orthogonal e pili ana i kahi lattice 3 Å x 5 Å huinahāhā (4H), kahi i ʻaelike maikaʻi loa me ke kumu hoʻohālike borophene. Eia kekahi, ʻike ʻia ka ʻike ʻekolu o ka ʻano o nā mea laina (1E) ʻae maikaʻi me ke ʻano nui like i nānā ʻia no nā pepa borophene.
Hōʻike ikaika kēia mau ʻike a pau i ka intercalation o ka graphene e ka borophene kokoke i nā ʻaoʻao o Ag, a no laila ke alakaʻi nei i ke kūkulu ʻana i nā heterostructures vertical borophene-graphene heterostructures, hiki ke hoʻokō pono ʻia ma ka hoʻonui ʻana i ka uhi mua o ka graphene.
4I he hōʻike schematic o kahi heterostructure kū i luna 4H, kahi e pili pono ai ke kuhikuhi o ka lalani boron (arrow arrow) me ke kuhikuhi zigzag o ka graphene (arrow eleele), pela i hana ai i rotationally proportional vertical heterostructure.
No ka ʻike kikoʻī hou aku me nā nuances o ke aʻo ʻana, manaʻo wau e nānā и iāia.
Epilogue
Ua hōʻike ʻia kēia haʻawina hiki i ka borophene ke hana i nā heterostructure ʻaoʻao a kū pololei me ka graphene. Hiki ke hoʻohanaʻia ia mau pūnaewele i ka hoʻomohalaʻana i nāʻano hou o nā meaʻelua-dimensional i hoʻohanaʻia i ka nanotechnology, hiki ke maʻalahi a hiki ke hoʻohanaʻia, a me nāʻano semiconductors hou.
Manaʻo ka poʻe noiʻi e hiki i kā lākou ulu ʻana ke hoʻoikaika ikaika i mua no nā ʻenehana pili uila. Eia nō naʻe, paʻakikī ka ʻōlelo ʻana e lilo kā lākou ʻōlelo i wānana. I kēia manawa, nui nā mea e noiʻi ʻia, hoʻomaopopo ʻia a noʻonoʻo ʻia i lilo kēlā mau manaʻo moʻokalaleo ʻepekema e hoʻopiha ana i ka noʻonoʻo o ka poʻe ʻepekema i mea maoli.
Mahalo no ka heluhelu ʻana, noʻonoʻo a hauʻoli maikaʻi nā kāne. 🙂
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