“Maye gurbi shine mabuɗin tona asirin juyin halitta. Hanyar ci gaba daga mafi sauƙi ga kwayoyin halitta zuwa nau'in halittu masu rinjaye yana da dubban shekaru. Amma duk shekara dubu dari ana samun ci gaba mai kaifi a cikin juyin halitta" (Charles Xavier, X-Men, 2000). Idan muka watsar da duk abubuwan almara-kimiyya da ke cikin ban dariya da fina-finai, to kalmomin Farfesa X gaskiya ne. Ci gaban wani abu yana ci gaba a ko'ina a yawancin lokaci, amma wani lokacin akwai tsalle-tsalle waɗanda ke da tasiri mai yawa akan tsarin gaba ɗaya. Wannan ya shafi ba kawai ga juyin halitta na nau'in ba, har ma da juyin halitta na fasaha, wanda babban abin da ke haifar da shi shine mutane, bincike da ƙirƙira. A yau za mu saba da binciken da, a cewar mawallafansa, shine ainihin juyin halitta a cikin nanotechnology. Ta yaya masana kimiyya suka fito ne daga Jami'ar arewa maso yamma (Amurka) ta sami sabon heretertocture biyu, me yasa aka zabi Borophene da Borophene da Borophene zaɓaɓɓu a matsayin abin da aka zaɓa na yau da kullun. Rahoton ƙungiyar bincike zai gaya mana game da wannan. Tafi
Tushen bincike
Mun sha jin kalmar "graphene" sau da yawa; yana da gyare-gyare mai girma biyu na carbon, wanda ya ƙunshi Layer na carbon atom 1 atom lokacin farin ciki. Amma "borofen" yana da wuyar gaske. Wannan kalma tana nufin kristal mai girma biyu wanda ya ƙunshi zarra na boron (B). Yiwuwar kasancewar borophene an fara annabta baya a tsakiyar 90s, amma a aikace yana yiwuwa a sami wannan tsarin sai 2015.
Tsarin atomic na borophene ya ƙunshi abubuwa uku masu kusurwa uku da hexagonal kuma sakamakon hulɗar tsakanin cibiyoyi biyu na tsakiya da na tsakiya a cikin jirgin sama, wanda ke da alaƙa ga abubuwan da ba su da wutar lantarki, waɗanda suka haɗa da boron.
*Ta hanyar haɗin yanar gizo na tsakiya biyu da multicenter muna nufin haɗin gwiwar sinadarai - hulɗar atom ɗin da ke siffanta daidaiton kwayar halitta ko crystal a matsayin tsari guda ɗaya. Misali, igiyar wutar lantarki ta tsakiya biyu tana faruwa ne lokacin da 2 atoms suka raba 2 electrons, kuma haɗin lantarki na tsakiya guda biyu yana faruwa lokacin da 2 atom da 3 electrons, da sauransu.
Daga ra'ayi na zahiri, borophene na iya zama mai ƙarfi kuma mafi sauƙi fiye da graphene. An kuma yi imani da cewa tsarin borophene zai iya zama mai tasiri ga batura, tun da borophene yana da ƙayyadaddun iyawa da ƙayyadaddun kayan lantarki na musamman da kayan jigilar ion. Koyaya, a halin yanzu wannan ka'ida ce kawai.
Kasancewa sinadarin trivalent*, boron yana da akalla 10 Allotropes*. A cikin nau'i mai nau'i biyu, kama polymorphism* ana kuma lura da shi.
Siffar Trivalent* iya kafa uku covalent bonds, valency wanda uku ne.
Allotropy* - lokacin da za'a iya gabatar da sinadari ɗaya a cikin nau'in abubuwa biyu ko fiye masu sauƙi. Alal misali, carbon - lu'u-lu'u, graphene, graphite, carbon nanotubes, da dai sauransu.
Polymorphism* - ikon wani abu ya wanzu a cikin sassa daban-daban na crystal (gyare-gyaren polymorphic). Game da abubuwa masu sauƙi, wannan kalma yana daidai da allotropy.
Ganin wannan polymorphism, an ba shi shawarar cewa Borophene na iya zama ɗan takarar da ke haifar da sabon abu biyu mai girma, tunda ya kamata a sake shakatar da bukatun da suka dace. Abin baƙin ciki shine, a baya an yi nazarin wannan batu na musamman a matakin ka'idar saboda matsalolin haɗin gwiwa.
Don kayan 2D na al'ada da aka samo daga lu'ulu'u masu yawa, ana iya samun tsarin heterostructures na tsaye ta amfani da tari na inji. A gefe guda kuma, nau'ikan heterostructures na gefe biyu suna dogara ne akan haɗin ƙasa zuwa sama. Madaidaicin tsarin heterostructures na atomically suna da babban yuwuwar magance matsalolin sarrafa aikin heterojunction, duk da haka, saboda haɗin gwiwar haɗin gwiwa, rashin kamala na lattice yawanci yana haifar da fa'ida da rikice-rikice. Saboda haka, akwai yuwuwar, amma akwai kuma matsaloli wajen gane shi.
A cikin wannan aikin, masu binciken sun gudanar da haɗakar da borophene da graphene a cikin nau'i mai nau'i biyu na heterostructure. Duk da rashin daidaituwar lattice crystallographic da daidaitawa tsakanin borophene da graphene, jeri na carbon da boron akan wani yanki na Ag(111) a ƙarƙashin matsananciyar matsananciyar ruwa (UHV) yana haifar da kusan madaidaicin tsaka-tsakin tsaka-tsakin tsaka-tsaki tare da daidaitawar lattice da aka annabta, haka kuma a tsaye heterointerfaces. .
Shiri na karatu
Kafin yin nazarin heterostructure, dole ne a ƙirƙira shi. An gudanar da haɓakar graphene da borophene a cikin ɗaki mai tsayi mai tsayi tare da matsa lamba na 1x10-10 millibars.
The guda crystal Ag (111) substrate an tsabtace ta da maimaita hawan keke na Ar + sputtering (1 x 10-5 millibar, 800 eV, 30 minutes) da thermal annealing (550 ° C, 45 minutes) don samun atomically mai tsabta da lebur Ag ( 111) ..
Graphene ya girma ta hanyar ƙawancen katako na lantarki mai tsabta (99,997%) graphite sanda tare da diamita na 2.0 mm akan wani Ag (750) mai zafi zuwa 111 ° C a halin yanzu na 1.6 A da ƙarfin lantarki na ~ 2 kV , wanda ke ba da halin yanzu na ~ 70 mA da hawan carbon ~ 40 nA. Matsi a cikin ɗakin ya kasance 1 x 10-9 millibars.
An girma Borophene ta hanyar ƙaurawar katako na lantarki na sandar boron mai tsabta (99,9999%) akan graphene submonolayer akan Ag (400) mai zafi zuwa 500-111 ° C. Filament halin yanzu ya kasance ~ 1.5 A kuma ƙarfin ƙarfin haɓaka ya kasance 1.75 kV, wanda ke ba da haɓakar halin yanzu na ~34 mA da juzu'in boron na ~10 nA. Matsa lamba a cikin ɗakin yayin girma na borophene ya kasance kusan 2 x 10-10 millibars.
Sakamakon bincike
Hoto #1
Akan hoton 1A aka nuna STM* Hoton girma na graphene, inda aka fi ganin wuraren graphene ta amfani da taswira dI/dV (1B), a ina I и V su ne tunneling halin yanzu da samfurin ƙaura, da d - yawa.
STM* - duban microscope na tunneling.
dI/dV taswirorin samfurin sun ba mu damar ganin mafi girma na ƙananan ƙananan jihohi na graphene idan aka kwatanta da Ag(111) substrate. Dangane da binciken da ya gabata, yanayin saman Ag (111) yana da sifa mai ma'ana, ya koma ga ingantaccen kuzari ta dI/dV graphene (1С), wanda ke bayyana mafi girman girman gida na jihohin graphene akan 1B ku 0.3v.
Akan hoton 1D za mu iya ganin tsarin guda-Layer graphene, inda saƙar zuma lattice da moire superstructure*.
Babban tsari* - siffa na tsarin fili na crystalline wanda ke maimaitawa a wani ɗan lokaci kuma don haka ya haifar da sabon tsari tare da lokacin canji daban-daban.
Moire* - superposition na biyu lokaci-lokaci raga alamu a saman juna.
A ƙananan yanayin zafi, haɓaka yana haifar da samuwar yankunan dendritic da lahani na graphene. Saboda raunin hulɗar tsakanin graphene da maƙallan da ke ƙasa, daidaitawar jujjuyawar graphene game da tushen Ag(111) ba na musamman ba ne.
Bayan saukar da boron, ana bincika microscopy na tunneling (1E) ya nuna kasancewar haɗin haɗin borophene da graphene. Hakanan ana iya gani a cikin hoton akwai yankuna a cikin graphene, waɗanda daga baya aka gano su azaman graphene da aka haɗa tare da borophene (wanda aka nuna a hoton. Gr/B). Abubuwan layin layi masu daidaitawa cikin kwatance uku kuma aka raba su da kusurwar 120° suma ana iya gani a fili a wannan yanki (kiban rawaya).
Hoto #2
Hoto a kunne 2Akazalika 1E, tabbatar da bayyanar cututtuka masu duhu a cikin graphene bayan ƙaddamar da boron.
Domin a yi nazarin waɗannan gyare-gyare da kyau da kuma gano asalinsu, an ɗauki wani hoto na yanki ɗaya, amma ta amfani da taswira | dlnI/dz| (2B), ku I - tunnel halin yanzu, d shi ne yawa, kuma z - Rabuwar bincike-samfurin (rata tsakanin allurar microscope da samfurin). Yin amfani da wannan fasaha yana ba da damar samun hotuna tare da ƙudurin sararin samaniya. Hakanan zaka iya amfani da CO ko H2 akan allurar microscope don wannan.
Hoto 2С Hoton da aka samu ta hanyar amfani da STM wanda titinsa aka lullube shi da CO. Kwatanta hotuna А, В и С yana nuna cewa duk abubuwan atomic an ayyana su azaman hexagons masu haske guda uku kusa da juna waɗanda aka nufa cikin kwatance guda biyu da ba su dace ba (jajaye da rawaya a cikin hotuna).
Manyan hotuna na wannan yanki (2D) tabbatar da cewa waɗannan abubuwan suna cikin yarjejeniya tare da boron dopant impurities, mamaye biyu graphene sublatices, kamar yadda aka nuna ta superimposed Tsarin.
CO shafi na microscope allura ya sa ya yiwu a bayyana tsarin geometric na takardar borophene (2E), wanda ba zai yiwu ba idan allurar ta kasance daidaitattun (karfe) ba tare da murfin CO ba.
Hoto #3
Samar da mu'ujizar heterointerface tsakanin borophene da graphene (3A) ya kamata ya faru lokacin da borophene ya girma kusa da yankunan graphene wanda ya riga ya ƙunshi boron.
Masana kimiyya sun tunatar da cewa a gefe heterointerfaces dogara a kan graphene-hBN (graphene + boron nitride) da lattice daidaito, da kuma heterojunctions dangane da canji karfe dichalcogenides suna da daidaito daidaito. A cikin yanayin graphene/borophene, yanayin ya ɗan bambanta - suna da ƙarancin tsarin kamanni dangane da madaidaicin lattice ko alamar ƙira. Duk da haka, duk da wannan, gefen graphene / borophene heterointerface yana nuna kusan cikakkiyar daidaiton atomic, tare da jagororin boron (B-jere) wanda ya dace da zigzag (ZZ) kwatance na graphene (3A) A 3B An nuna babban hoto na yankin ZZ na heterointerface (layukan shuɗi suna nuna abubuwan da suka dace da haɗin gwiwar boron-carbon covalent).
Tunda borophene ke tsiro a ƙananan zafin jiki idan aka kwatanta da graphene, gefuna na yankin graphene ba zai yuwu su sami babban motsi ba yayin samar da haɗin gwiwa tare da borophene. Sabili da haka, kusan madaidaicin mahallin mahaɗar ra'ayi mai yuwuwa sakamakon daidaitawa daban-daban da halayen haɗin gwiwar boron. Duban duban gani na spectroscopy (3С) da bambancin ramukan ramuka (3D) nuna cewa canjin lantarki daga graphene zuwa borophene yana faruwa a kan nisa na ~ 5 Å ba tare da bayyanar da alamun bayyanar ba.
Akan hoton 3E An nuna hotunan duban ramuka guda uku da aka ɗauka tare da layukan da ba a taɓa gani ba a cikin 3D, waɗanda ke tabbatar da cewa wannan gajeriyar canjin lantarki ba ta da hankali ga tsarin tsaka-tsakin gida kuma yana kwatankwacin wancan a musaya na borophene-azurfa.
Hoto #4
Graphene hulda* Hakanan an yi nazari sosai a baya, amma jujjuyawar masu shiga tsakani zuwa zanen gado na 2D na gaskiya yana da wuya.
Sadarwa* - sake jujjuyawa hada kwayoyin ko rukuni na kwayoyin halitta tsakanin wasu kwayoyin halitta ko kungiyoyin kwayoyin halitta.
Ƙananan radius atomic na boron da raunin hulɗar tsakanin graphene da Ag(111) suna ba da shawarar yiwuwar haɗuwa da graphene tare da boron. A cikin hoton 4A Ana gabatar da shaida ba kawai na haɗin gwiwar boron ba, har ma da samuwar sinadarai na borophene-graphene a tsaye, musamman yankunan triangular da ke kewaye da graphene. Lattice na saƙar zuma da aka gani akan wannan yanki na uku yana tabbatar da kasancewar graphene. Koyaya, wannan graphene yana nuna ƙananan ƙananan ƙananan jihohi a -50 meV idan aka kwatanta da graphene kewaye (4B). Idan aka kwatanta da graphene kai tsaye akan Ag(111), babu wata shaida ta babban yawan jihohi a cikin bakan. dI/dV (4C, shuɗi mai lankwasa), wanda yayi daidai da yanayin saman Ag(111), shine shaidar farko ta haɗin gwiwar boron.
Hakanan, kamar yadda ake tsammani don tsaka-tsaki na ɗan lokaci, graphene lattice ya ci gaba da ci gaba da kasancewa a cikin keɓancewa ta gefe tsakanin graphene da yankin triangular (4D - yayi daidai da yanki rectangular akan 4A, da'ira cikin jajayen layi mai dige-dige). Hoton da aka yi amfani da CO akan allurar microscope shima ya tabbatar da kasancewar gurɓataccen maye gurbin boron (4E - yayi daidai da yanki rectangular akan 4A.
An kuma yi amfani da allurar microscope ba tare da wani sutura ba yayin bincike. A wannan yanayin, an bayyana alamun abubuwa masu madaidaici guda ɗaya tare da lokaci na 5 Å a cikin sassan graphene masu tsaka-tsaki (4F и 4G). Waɗannan sifofi guda ɗaya sun yi kama da layuka na boron a cikin ƙirar borophene. Baya ga saitin maki daidai da graphene, Fourier yana canza hoton zuwa 4G yana nuna maki biyu na orthogonal daidai da lattice rectangular 3 Å x 5 Å (4h ku), wanda ke cikin kyakkyawar yarjejeniya tare da samfurin borophene. Bugu da kari, da aka lura sau uku fuskantarwa na tsararrun abubuwa masu linzami (1E) ya yarda da kyau tare da tsarin da aka fi dacewa da aka lura don zanen borophene.
Duk waɗannan abubuwan lura suna ba da shawarar haɗin gwiwar graphene ta borophene kusa da gefuna na Ag, wanda saboda haka yana haifar da samuwar borophene-graphene heterostructures na tsaye, wanda za'a iya samun fa'ida ta hanyar haɓaka ɗaukar hoto na graphene.
4I wakilcin tsari ne na wani tsari na tsaye a kan 4H, Inda jagorar layin boron (kibiyar ruwan hoda) ta yi daidai da al'amuran zigzag na graphene (baƙar kibiya), ta haka ne ke yin jujjuyawar daidaitaccen tsari na tsaye.
Don ƙarin cikakken sani tare da nuances na binciken, Ina ba da shawarar dubawa и masa.
Epilogue
Wannan binciken ya nuna cewa borophene yana da ikon samar da sifofin heterostructure na gefe da na tsaye tare da graphene. Irin wannan tsarin za a iya amfani dashi a cikin ci gaban sababbin abubuwa masu girma guda biyu da aka yi amfani da shi a cikin neenchneknics, sassauƙa da masu lantarki da kuma sabbin hanyoyin semiconductucntor.
Masu binciken da kansu sun yi imanin cewa ci gaban su na iya zama babban ci gaba ga fasahar da ke da alaƙa da lantarki. Duk da haka, yana da wuya a ce da tabbaci cewa kalmominsu za su zama annabci. A halin yanzu, akwai sauran abubuwa da yawa da za a yi bincike, fahimta da ƙirƙira ta yadda waɗannan ra'ayoyin almara na kimiyya waɗanda ke cika zukatan masana kimiyya su zama cikakkiyar gaskiya.
Na gode da karantawa, ku kasance da sha'awar kuma kuyi kyakkyawan mako. 🙂
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source: www.habr.com