“Ho fetoha ha liphatsa tsa lefutso ke senotlolo sa ho senola sephiri sa ho iphetola ha lintho. Tsela ea tsoelo-pele ho tloha ho sebōpuoa se bonolo ka ho fetisisa ho ea ho mefuta e mengata ea likokoana-hloko e nka lilemo tse likete. Empa lilemo tse ling le tse ling tse likete tse lekholo ho na le lebelo le matla la ho iphetola ha lintho" (Charles Xavier, X-Men, 2000). Haeba re lahla likarolo tsohle tsa tšōmo ea mahlale tse teng metlae le lifiliming, joale mantsoe a Moprofesa X ke 'nete haholo. Tsoelo-pele ea ntho e tsoela pele ka mokhoa o lekanang ka nako e ngata, empa ka linako tse ling ho na le ho qhoma ho nang le tšusumetso e kholo ts'ebetsong eohle. Sena ha se sebetse feela ho iphetola ha lintho tsa mefuta, empa hape le ho iphetola ha thekenoloji, mokhanni ea ka sehloohong oa batho, lipatlisiso le liqapi tsa bona. Kajeno re tla tloaelana le thuto eo, ho ea ka bangoli ba eona, e leng phetoho ea sebele ea ho iphetola ha lintho ho nanotechnology. Bo-rasaense ba tsoang Univesithing ea Northwestern (USA) ba khonne joang ho theha heterostructure e ncha ea mahlakore a mabeli, hobaneng ho ile ha khethoa graphene le borophene e le motheo, hona tsamaiso e joalo e ka ba le thepa efe? Tlaleho ea sehlopha sa lipatlisiso e tla re bolella ka sena. Eya.
Motheo oa lipatlisiso
Re utloile lentsoe "graphene" hangata; ke phetoho ea mahlakore a mabeli ea carbon, e nang le lera la liathomo tsa carbon 1 athomo e teteaneng. Empa "borofen" ha e fumanehe haholo. Lentsoe lena le bolela kristale ea mahlakore a mabeli e nang le liathomo tsa boron (B) feela. Monyetla oa ho ba teng ha borophene o ile oa boleloa esale pele morao koana bohareng ba lilemo tsa bo-90, empa ka ts'ebetso sebopeho sena se fumanoe feela ka 2015.
Sebopeho sa athomo sa borophene se na le likarolo tse tharo le tse mahlakore a mararo 'me ke phello ea ho sebelisana pakeng tsa li-bond tse peli le tse ngata tse bohareng ba sefofane, e leng ntho e tloaelehileng haholo bakeng sa likarolo tse haelloang ke elektronike, tse kenyelletsang boron.
*Ka li-bond tse peli tse bohareng le tse ngata re bolela litlamo tsa lik'hemik'hale - litšebelisano tsa liathomo tse bontšang botsitso ba molek'hule kapa kristale e le sebopeho se le seng. Ka mohlala, li-electrone tse peli tse bohareng tse peli li etsahala ha liathomo tse 2 li arolelana lielektrone tse 2, 'me setsi sa bobeli sa li-electrone tse tharo se etsahala ha liathomo tse 2 le li-electrone tse 3, joalo-joalo.
Ho ea ka pono ea 'mele, borophene e ka ba matla le ho fetoha habonolo ho feta graphene. Hape ho lumeloa hore mehaho ea borophene e ka ba motlatsi o atlehang oa libeteri hobane borophene e na le matla a phahameng a khethehileng le thepa e ikhethang ea elektronike le thepa ea lipalangoang tsa ion. Leha ho le joalo, hajoale ena ke khopolo feela.
Ho ba trivalent element*, boron e na le bonyane 10 allotropes*. Ka sebopeho sa mahlakore a mabeli, se tšoanang polymorphism* e boetse e bonoa.
Trivalent element* e khonang ho etsa litlamo tse tharo tsa covalent, tseo valency ea tsona e leng tse tharo.
Allotropy* - ha ntho e le 'ngoe ea lik'hemik'hale e ka hlahisoa ka mokhoa oa lintho tse peli kapa ho feta tse bonolo. Ka mohlala, carbon - daemane, graphene, graphite, carbon nanotubes, joalo-joalo.
Polymorphism* - bokhoni ba ntho e ka bang teng ka har'a likarolo tse fapaneng tsa kristale (liphetoho tsa polymorphic). Tabeng ea lintho tse bonolo, lentsoe lena le tšoana le allotropy.
Ka lebaka la polymorphism ena e pharaletseng, ho khothaletsoa hore borophene e ka ba mokhethoa ea hloahloa bakeng sa ho theha li-heterostructures tse ncha tsa mahlakore a mabeli, kaha litlhophiso tse fapaneng tsa boron li lokela ho fokotsa litlhoko tsa ho bapisa lithapo. Ka bomalimabe, taba ena e kile ea ithutoa ka mokhoa o ikhethileng maemong a theory ka lebaka la mathata a ho kopanya.
Bakeng sa lisebelisoa tse tloaelehileng tsa 2D tse fumanoeng ho tsoa likristale tse ngata tse nang le lera, li-heterostructures tse otlolohileng li ka bonoa ho sebelisoa stacking ea mochini. Ka lehlakoreng le leng, li-heterostructures tse peli-dimensional lateral li thehiloe holim'a motsoako o ka tlaase ho ea holimo. Li-heterostructures tsa morao-rao tse hlakileng li na le monyetla o moholo oa ho rarolla mathata a taolo ea ts'ebetso ea heterojunction, leha ho le joalo, ka lebaka la tlamahano e kopanetsoeng, ho nyallana ha li-lattice tse sa phethahalang hangata ho fella ka likhokahano tse pharaletseng le tse sa hlakang. Ka hona, ho na le bokhoni, empa ho boetse ho na le mathata ho e hlokomela.
Mosebetsing ona, bafuputsi ba khonne ho kopanya borophene le graphene ho heterostructure e le 'ngoe ea mahlakore a mabeli. Leha ho na le phapang pakeng tsa borophene le graphene, ho behelloa ka tatellano ha carbon le boron holim'a substrate ea Ag (111) tlas'a vacuum e phahameng haholo (UHV) ho fella ka li-heterointerfaces tse nepahetseng ka ho fetisisa tse nang le litekanyo tse boletsoeng esale pele tsa lattice, hammoho le li-heterointerfaces tse boletsoeng esale pele. .
Boitokisetso ba ho ithuta
Pele o ithuta ka heterostructure, e ne e tlameha ho etsoa. Khōlo ea graphene le borophene e ne e etsoa ka kamoreng ea "vacuum" e phahameng ka ho fetisisa e nang le khatello ea 1x10-10 millibars.
Karoloana e le 'ngoe ea kristale Ag (111) e ile ea hloekisoa ka makhetlo a mangata a Ar+ sputtering (1 x 10-5 millibar, 800 eV, metsotso e 30) le annealing ea mocheso (550 ° C, metsotso e 45) ho fumana Ag e hloekileng le e bataletseng. 111) holimo. .
Graphene e holisitsoe ka mouoane oa electron beam oa rod e hloekileng (99,997%) ea graphite e bophara ba 2.0 mm holim'a substrate ea Ag (750) e futhumetseng ho isa ho 111 °C ka mocheso oa hona joale oa ~ 1.6 A le motlakase o potlakileng oa ~ 2 kV. , e fanang ka tlhahiso ea hona joale ea ~ 70 mA le carbon flux ~ 40 nA. Khatello ka kamoreng e ne e le 1 x 10-9 millibar.
Borophene e holisitsoe ka moea oa elektrone beam ea mouoane oa boron rod e hloekileng (99,9999%) ho submonolayer graphene ka Ag (400) e futhumetseng ho isa ho 500-111 °C. The filament current e ne e le ~ 1.5 A mme motlakase o potlakisang e ne e le 1.75 kV, e fanang ka tlhahiso ea hona joale ea ~34 mA le phallo ea boron ea ~10 nA. Khatello ka kamoreng nakong ea kholo ea borophene e ne e le hoo e ka bang 2 x 10-10 millibars.
Liphetho tsa lipatlisiso
Setšoantšo #1
Setšoantšong 1A bontshiweng STM* sets'oants'o sa graphene e seng e holile, moo libaka tsa graphene li bonoang hantle ho sebelisoa 'mapa dI/dV (1B), kae I и V ke phetisetso ea hajoale le mohlala oa phalliso, le d - ho teteana.
STM* - ho hlahloba microscope.
dI/dV limmapa tsa sampole li re lumelletse ho bona bongata bo phahameng ba libaka tsa graphene ha bo bapisoa le substrate ea Ag(111). Ho latela lithuto tse fetileng, boemo ba Ag (111) bo na le sebopeho sa mohato, se fetiselitsoeng ho matla a nepahetseng ka ho fetesisa. dI/dV boholo ba graphene (1С), e hlalosang bongata bo phahameng ba lehae ba linaha tsa graphene ka 1B ho 0.3 eV.
Setšoantšong 1D re ka bona sebopeho sa single-layer graphene, moo khekhe ea linotsi le moiré superstructure*.
Superstructure* - karolo ea sebopeho sa motsoako oa kristale o pheta-phetoang ka nako e itseng 'me kahoo o theha mohaho o mocha o nang le nako e fapaneng ea ho fapanyetsana.
Moire* - superposition ea mekhoa e 'meli ea mesh ea nakoana ka holim'a e' ngoe.
Lithempereichara tse tlase, kholo e lebisa ho thehoeng ha libaka tsa dendritic le tse senyehileng tsa graphene. Ka lebaka la litšebelisano tse fokolang lipakeng tsa graphene le karolo e ka tlase ea motheo, tokiso ea potoloho ea graphene mabapi le Ag(111) e ka tlase ha e ikhethang.
Ka mor'a ho kenngoa ha boron, ho hlahloba microscopy ea tunnel (1E) e bontšitse boteng ba motsoako oa libaka tsa borophene le graphene. Hape ho bonahalang setšoantšong ke libaka tse ka hare ho graphene, tseo hamorao li ileng tsa tsejoa e le graphene e hokahaneng le borophene (e bontšitsoeng setšoantšong). Gr/B). Lintho tse nang le mela e lebisitsoeng ka mahlakoreng a mararo 'me li arotsoe ka angle ea 120 ° le tsona li bonahala ka ho hlaka sebakeng sena (metsu e mosehla).
Setšoantšo #2
Senepe se butswe 2Ahape 1E, netefatsa ponahalo ea ho tepella ho lefifi sebakeng sa graphene ka mor'a ho kenngoa ha boron.
E le ho hlahloba libopeho tsena hantle le ho tseba hore na li simolohile hokae, ho ile ha nkoa setšoantšo se seng sa sebaka seo, empa ho sebelisoa limmapa |dlnI/dz| (2B), moo I - kotopo ea motlakase, d ke density, le z - karohano ea mohlala oa probe (lekhalo pakeng tsa nale ea microscope le sampole). Tšebeliso ea mokhoa ona e etsa hore ho khonehe ho fumana litšoantšo tse nang le qeto e phahameng ea sebaka. U ka boela ua sebelisa CO kapa H2 ho nale ea microscope bakeng sa sena.
Image Image 2С ke setšoantšo se fumanoeng ho sebelisoa STM eo ntlha ea eona e neng e koahetsoe ka CO. Papiso ea litšoantšo А, В и С e bontša hore likarolo tsohle tsa athomo li hlalosoa e le li-hexagon tse tharo tse khanyang tse haufi tse lebisitsoeng ka mahlakoreng a mabeli a sa tšoaneng (likhutlo-tharo tse khubelu le tse mosehla lifotong).
Litšoantšo tse atolositsoeng tsa sebaka sena (2D) netefatsa hore lintlha tsena li lumellana le litšila tsa boron dopant, tse nang le li-graphene sublattices tse peli, joalokaha ho bontšoa ke mehaho e holimo.
Ho roala ha nale ea microscope ho entse hore ho khonehe ho senola sebopeho sa geometri sa letlapa la borophene (2E), e neng e ke ke ea khoneha haeba nale e ne e le e tloaelehileng (tšepe) ntle le ho roala CO.
Setšoantšo #3
Ho thehoa ha lateral heterointerfaces pakeng tsa borophene le graphene (3A) e lokela ho etsahala ha borophene e hola haufi le libaka tsa graphene tse seng li na le boron.
Bo-rasaense ba hopotsa hore li-lateral heterointerfaces tse thehiloeng ho graphene-hBN (graphene + boron nitride) li na le li-lattice consistency, 'me li-heterojunctions tse thehiloeng ho transition metal dichalcogenides li na le symmetry consistency. Tabeng ea graphene/borophene, boemo bo fapane hanyane - ba na le sebopeho se fokolang sa sebopeho ho latela li-lattice constants kapa crystal symmetry. Leha ho le joalo, ho sa tsotelehe sena, lateral graphene/borophene heterointerface e bonts'a tumellano e batlang e lekana hantle ea athomo, ka litsela tsa mola oa boron (B-row) tse tsamaellanang le litsela tsa zigzag (ZZ) tsa graphene (3A). Bulela 3B setšoantšo se holisitsoeng sa sebaka sa ZZ sa heterointerface se bontšoa (mela e putsoa e bontša likarolo tsa sefahleho tse lumellanang le boron-carbon covalent bonds).
Kaha borophene e hola ka mocheso o tlase ha o bapisoa le graphene, mathōko a sebaka sa graphene ha ho bonolo hore a be le motsamao o phahameng ha ho etsoa heterointerface le borophene. Ka hona, heterointerface e batlang e nepahetse ka athomo e kanna ea ba ka lebaka la litlhophiso le litšobotsi tse fapaneng tsa libonto tsa boron tse ngata. Ho hlahloba spectroscopy spectroscopy (3С) le conductivity e fapaneng ea kotopo (3D) bontša hore phetoho ea elektronike ho tloha ho graphene ho ea ho borophene e etsahala ka sebaka se selelele sa ~ 5 Å se se nang li-interface tse bonahalang.
Setšoantšong 3E Ho bonts'itsoe lipono tse tharo tsa "scanning spectroscopy spectroscopy" tse nkuoeng ho bapa le mela e meraro e nchocho ho 3D, tse tiisang hore phetoho ena e khuts'oane ea elektroniki ha e amehe ho meaho ea lehae e kopaneng 'me e bapisoa le ea likhokahano tsa borophene-silver.
Setšoantšo #4
Graphene puisano* e boetse e kile ea ithutoa haholo, empa phetoho ea li-intercalants hore e be maqephe a 'nete a 2D ha e fumanehe ka seoelo.
Intercalation* - kenyelletso e ka fetoloang ea molek'hule kapa sehlopha sa limolek'hule lipakeng tsa limolek'hule tse ling kapa lihlopha tsa limolek'hule.
Radiase e nyane ea athomo ea boron le tšebelisano e fokolang lipakeng tsa graphene le Ag(111) li fana ka maikutlo a ho hokahanya ha graphene le boron. Setšoantšong 4A bopaki bo hlahisoa eseng feela ka ho kena-kenana le boron, empa hape le ho thehoa ha li-heterostructures tsa borophene-graphene tse otlolohileng, haholo-holo libaka tse tharo tse pota-potiloeng ke graphene. Lekhetla la mahe a linotši le bonoang sebakeng sena sa kgutlotharo le tiisa boteng ba graphene. Leha ho le joalo, graphene ena e bonts'a sekhahla se tlase sa linaha ho -50 meV ha se bapisoa le graphene e haufi.4B). Ha ho bapisoa le graphene ka kotloloho ho Ag(111), ha ho na bopaki ba hore ho na le palo e phahameng ea linaha sebakeng sa spectrum. dI/dV (4C, curve blue), e tsamaellanang le boemo ba bokaholimo ba Ag(111), ke bopaki ba pele ba ho kopana ha boron.
Hape, joalo ka ha ho lebelletsoe bakeng sa ho kena-kenana ha karolo e itseng, graphene lattice e lula e tsoela pele ho pholletsa le sebopeho sa lateral pakeng tsa graphene le sebaka se tharo (4D - e tsamaellana le sebaka sa khutlonnetsepa ho 4A, e pota-potiloe ka mola oa matheba a mafubelu). Setšoantšo se sebelisang CO holim'a nale ea microscope se boetse se tiisa boteng ba litšila tsa boron (4E - e tsamaellana le sebaka sa khutlonnetsepa ho 4A, e pota-potiloeng ka mola o matheba o mosehla).
Linale tsa microscope ntle le ho roala leha e le efe li ile tsa boela tsa sebelisoa nakong ea tlhahlobo. Tabeng ena, matšoao a likarolo tse nang le moeli o le mong o nang le periodicity ea 5 Å a senotsoe libakeng tse hokahaneng tsa graphene (4F и 4G). Mehaho ena ea lehlakore le le leng e tšoana le mela ea boron ea mohlala oa borophene. Ho phaella ho sete ea lintlha tse tsamaellanang le graphene, Fourier fetola setšoantšo ho 4G e bonts'a lintlha tse peli tsa orthogonal tse tsamaellanang le 3 Å x 5 Å latice rectangular (4H), e lumellanang hantle le mohlala oa borophene. Ntle le moo, ho shebiloe maemo a mararo a letoto la likarolo tsa mola (1E) e lumellana hantle le mohaho o tšoanang o ka sehloohong o hlokometsoeng bakeng sa maqephe a borophene.
Maikutlo ana kaofela a fana ka maikutlo a matla a ho hokahana ha graphene ka borophene haufi le mathōko a Ag, e leng se lebisang ho thehoeng ha li-heterostructures tsa borophene-graphene tse otlolohileng, tse ka fumanoang ka mokhoa o molemo ka ho eketsa tšireletso ea pele ea graphene.
4I ke setšoantšo sa moralo oa heterostructure e emeng holim'a 4H, moo tataiso ea mola oa boron (motsu o mopinki) o tsamaellanang haufi-ufi le tataiso ea zigzag ea graphene (motsu o motšo), kahoo e etsa heterostructure e otlolohileng e lekanang.
Bakeng sa ho tseba haholoanyane ka li-nuances tsa thuto, ke khothaletsa ho sheba и ho eena.
Epilogue
Phuputso ena e bontšitse hore borophene e khona ho etsa li-heterostructures tse ka morao le tse otlolohileng ka graphene. Mekhoa e joalo e ka sebelisoa ho nts'etsopele ea mefuta e mecha ea likarolo tse peli tse sebelisoang ho nanotechnology, lisebelisoa tsa elektronike tse feto-fetohang le tse apereng, hammoho le mefuta e mecha ea li-semiconductors.
Bafuputsi ka bobona ba lumela hore nts'etsopele ea bona e ka ba ts'ebetso e matla ea tsoelo-pele ea mahlale a amanang le elektroniki. Leha ho le joalo, ho ntse ho le thata ho bolela ka tieo hore mantsoe a bona e tla ba boprofeta. Hona joale, ho ntse ho e-na le lintho tse ngata tse lokelang ho etsoa lipatlisiso, ho utloisisoa le ho qaptjoa e le hore likhopolo tseo tsa saense tse iqapetsoeng tse tlatsang likelello tsa bo-rasaense e be 'nete e feletseng.
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Source: www.habr.com