Muna amfani da na'urar daukar hoto ta lokaci da kusurwa da aka warware (tr-ARPES) don bincika canja wurin caji mai sauri a cikin wani tsarin epitaxial heterostructure da aka yi da monolayer WS2 da graphene. Wannan tsarin heterostructure ya haɗa fa'idodin semiconductor mai rata kai tsaye tare da haɗin gwiwar juyawa mai ƙarfi da kuma hulɗar haske mai ƙarfi tare da na masu ɗaukar kaya marasa nauyi na semimetal tare da motsi mai yawa da tsawon rayuwar juyawa. Mun gano cewa, bayan fitowar haske a cikin amsawa ga A-exciton a cikin WS2, ramukan da aka haskaka suna canzawa cikin sauri zuwa cikin layin graphene yayin da electrons masu haskakawa ke ci gaba da kasancewa a cikin layin WS2. An gano cewa yanayin wucin gadi da aka raba caji yana da tsawon rai na ~ 1 ps. Mun danganta bincikenmu da bambance-bambance a cikin sararin yanayi mai warwatse wanda ya haifar da daidaituwar madaurin WS2 da graphene kamar yadda ARPES mai ƙuduri mai girma ya bayyana. Tare da haɓakar gani mai zaɓin juyawa, tsarin WS2/graphene da aka bincika na iya samar da dandamali don ingantaccen allurar juyawa ta gani zuwa graphene.
Samuwar kayan aiki iri-iri masu girma biyu ya buɗe damar ƙirƙirar sabbin siraran heterostructures tare da sabbin ayyuka bisa ga tantancewar dielectric da aka ƙera da kuma tasirin kusanci daban-daban (1-3). An cimma na'urori masu tabbatar da ƙa'idodi don aikace-aikacen nan gaba a fannin lantarki da optoelectronics (4-6).
A nan, mun mayar da hankali kan tsarin epitaxial van der Waals heterostructures wanda ya ƙunshi monolayer WS2, wani semiconductor mai rata kai tsaye tare da haɗin juyawa mai ƙarfi da kuma babban raba juyi na tsarin band saboda karyewar inversion symmetry (7), da kuma monolayer graphene, wani semimetal mai tsarin conical band da kuma babban motsi mai ɗaukar kaya (8), wanda aka girma akan hydrogen-ended SiC (0001). Alamun farko don canja wurin caji mai sauri (9-15) da tasirin juyawa-orbit da ke haifar da kusanci (16-18) sun sa WS2/graphene da makamantansu heterostructures su zama masu alƙawarin yin amfani da optoelectronic (19) da optospintronic (20) nan gaba.
Mun fara bayyana hanyoyin shakatawa na nau'ikan ramukan electron da aka samar ta hanyar photoemission a cikin WS2/graphene tare da photoemission spectroscopy na lokaci da kusurwa (tr-ARPES). Don wannan dalili, muna motsa heterostructure tare da bugun famfo 2-eV wanda ke amsawa ga A-exciton a cikin WS2 (21, 12) kuma muna fitar da photoelectrons tare da bugun bincike na jinkiri na biyu a cikin kuzarin photon 26-eV. Muna ƙayyade kuzarin motsi da kusurwar fitarwa na photoelectrons tare da mai nazarin hemispherical azaman aikin jinkirin binciken famfo don samun damar shiga yanayin motsi, makamashi, da lokaci. ƙudurin makamashi da lokaci shine 240 meV da 200 fs, bi da bi.
Sakamakonmu ya ba da shaida kai tsaye don canja wurin caji mai sauri tsakanin layukan da aka daidaita da epitaxial, yana tabbatar da alamun farko bisa ga duk dabarun gani a cikin irin waɗannan tsarin heterostructures da aka haɗa da hannu tare da daidaitawar azimuthal na yadudduka (9-15). Bugu da ƙari, mun nuna cewa wannan canja wurin caji ba shi da daidaito sosai. Ma'auninmu yana nuna yanayin wucin gadi da ba a lura da shi ba wanda aka riga aka lura da caji tare da electrons masu ɗaukar hoto da ramuka waɗanda ke cikin layin WS2 da graphene, bi da bi, wanda ke rayuwa na kusan ps 1. Muna fassara bincikenmu dangane da bambance-bambance a cikin sararin watsewa don canja wurin electron da rami wanda ya haifar da daidaituwar madaukai na WS2 da graphene kamar yadda aka bayyana ta hanyar babban ƙudurin ARPES. Idan aka haɗa shi da zugawar gani mai juyawa da kwarin-zaɓi (22-25), WS2/graphene heterostructures na iya samar da sabon dandamali don ingantaccen allurar juyawa mai gani cikin graphene.
Siffa ta 1A ta nuna ma'aunin ARPES mai ƙuduri mai girma da aka samu tare da fitilar helium na tsarin madauri tare da alkiblar ΓK na epitaxial heterostructure WS2/graphene. An gano cewa mazubin Dirac yana da rami tare da wurin Dirac wanda yake kusa da 0.3 eV sama da ƙarfin sinadaran daidaito. An gano saman madaurin valence na WS2 mai juyawa yana kusa da 1.2 eV ƙasa da ƙarfin sinadaran daidaito.
(A) Daidaiton hasken wutar lantarki da aka auna tare da alkiblar ΓK tare da fitilar helium mara polarized. (B) Hasken wutar lantarki don jinkirin binciken famfo mara kyau wanda aka auna tare da bugun ultraviolet mai tsauri na p-polarized a ƙarfin photon 26-eV. Layukan launin toka da ja masu launin ja suna nuna matsayin bayanan layin da aka yi amfani da su don fitar da matsayin kololuwar wucin gadi a Hoto na 2. (C) Canje-canjen da famfo ya haifar na hasken wutar lantarki 200 fs bayan fitowar haske a makamashin photon famfo na 2 eV tare da tasirin famfo na 2 mJ/cm2. An nuna riba da asarar hasken photoelectrons da ja da shuɗi, bi da bi. Akwatunan suna nuna yankin haɗakar alamun binciken famfo da aka nuna a Hoto na 3.
Siffa ta 1B ta nuna hoton tr-ARPES na tsarin band kusa da maki WS2 da graphene K da aka auna da bugun ultraviolet mai tsanani 100-fs a ƙarfin photon 26-eV a jinkirin gwajin famfo kafin isowar bugun famfo. A nan, ba a warware rabuwar juyawa ba saboda lalacewar samfurin da kuma kasancewar bugun famfo na 2-eV wanda ke haifar da faɗaɗa cajin sarari na fasalulluka na spectral. Siffa ta 1C ta nuna canje-canjen da famfo ya haifar na hasken photocurrent dangane da Siffa ta 1B a jinkirin gwajin famfo na 200 fs inda siginar gwajin famfo ta kai matsakaicinta. Launuka ja da shuɗi suna nuna riba da asarar hasken photoelectrons, bi da bi.
Domin yin nazarin wannan ƙarfin kuzari mai yawa, da farko za mu tantance matsayin kololuwar wucin gadi na band ɗin valence na WS2 da band ɗin graphene π tare da layukan da aka lanƙwasa a cikin Hoto na 1B kamar yadda aka bayyana dalla-dalla a cikin Kayan Ƙarin. Mun gano cewa band ɗin valence na WS2 yana canzawa sama da 90 meV (Hoto na 2A) kuma band ɗin graphene π yana canzawa ƙasa da 50 meV (Hoto na 2B). An gano cewa tsawon rayuwar waɗannan canje-canjen shine 1.2 ± 0.1 ps don band ɗin valence na WS2 da 1.7 ± 0.3 ps don band ɗin graphene π. Waɗannan canje-canjen kololuwar suna ba da shaidar farko ta caji na wucin gadi na layuka biyu, inda ƙarin cajin tabbatacce (mara kyau) yana ƙaruwa (rage) kuzarin ɗaurewar yanayin lantarki. Lura cewa haɓaka band ɗin valence na WS2 yana da alhakin siginar binciken famfo mai bayyana a yankin da akwatin baƙar fata ya alama a cikin Hoto na 1C.
Canji a matsayin kololuwar ma'aunin valence na WS2 (A) da graphene π-band (B) a matsayin aikin jinkirin binciken famfo tare da dacewa da exponential (layuka masu kauri). Tsawon lokacin canjin WS2 a cikin (A) shine 1.2 ± 0.1 ps. Tsawon lokacin canjin graphene a cikin (B) shine 1.7 ± 0.3 ps.
Na gaba, mun haɗa siginar binciken famfo a kan wuraren da akwatunan masu launi suka nuna a Hoto na 1C kuma muka tsara sakamakon ƙidayar a matsayin aikin jinkirin binciken famfo a Hoto na 3. Lanƙwasa 1 a Hoto na 3 yana nuna yanayin masu ɗaukar hoto da ke kusa da ƙasan band ɗin watsawa na Layer WS2 tare da tsawon rai na 1.1 ± 0.1 ps da aka samu daga dacewa mai ƙarfi ga bayanai (duba Kayan Ƙarin).
Binciken famfo a matsayin aikin jinkiri da aka samu ta hanyar haɗa hasken lantarki a kan yankin da akwatunan da ke cikin Hoto na 1C suka nuna. Layukan masu kauri sun dace da bayanai. Lanƙwasa (1) Yawan masu ɗaukar kaya na wucin gadi a cikin hanyar sadarwa ta WS2. Lanƙwasa (2) Siginar binciken famfo na π-band na graphene sama da ƙarfin sinadaran daidaito. Lanƙwasa (3) Siginar binciken famfo na π-band na graphene a ƙasa da ƙarfin sinadaran daidaito. Lanƙwasa (4) Siginar binciken famfo mai ƙarfi a cikin hanyar valence na WS2. An gano cewa tsawon rayuwar shine 1.2 ± 0.1 ps a cikin (1), 180 ± 20 fs (riba) da ~2 ps (asara) a cikin (2), da 1.8 ± 0.2 ps a cikin (3).
A cikin lanƙwasa na 2 da 3 na Hoto na 3, mun nuna siginar binciken famfo na graphene π-band. Mun gano cewa ribar electrons sama da ƙarfin sinadarai na daidaito (lanƙwasa na 2 a Hoto na 3) yana da ɗan gajeren rayuwa (180 ± 20 fs) idan aka kwatanta da asarar electrons a ƙasa da ƙarfin sinadarai na daidaito (1.8 ± 0.2 ps a lanƙwasa na 3 Hoto na 3). Bugu da ƙari, an gano cewa ribar farko ta hasken rana a lanƙwasa na 2 na Hoto na 3 ta zama asara a t = 400 fs tare da tsawon rai na ∼2 ps. An gano rashin daidaito tsakanin riba da asara ba ya nan a cikin siginar binciken famfo na graphene monolayer da ba a rufe ba (duba hoto na S5 a cikin Kayan Ƙarin), yana nuna cewa rashin daidaituwar sakamakon haɗin kai tsakanin layers a cikin heterostructure na WS2/graphene. Lura da raguwar riba mai ɗorewa da kuma asarar da ta daɗe tana faruwa a sama da ƙasa da ƙarfin sinadarai na daidaito, bi da bi, yana nuna cewa ana cire electrons cikin inganci daga layin graphene bayan ɗaukar hoto na heterostructure. Sakamakon haka, layin graphene yana samun caji mai kyau, wanda ya yi daidai da ƙaruwar kuzarin ɗaurewa na π-band da aka samu a Hoto na 2B. Saukar da π-band ɗin yana cire wutsiyar ƙarfi mai yawa na daidaiton Fermi-Dirac daga sama da ƙarfin sinadarai na daidaito, wanda ke bayyana wani ɓangare na canjin alamar siginar famfo-probe a cikin lanƙwasa na 2 na Hoto na 3. Za mu nuna a ƙasa cewa wannan tasirin yana ƙara ƙaruwa ta hanyar asarar electrons na ɗan lokaci a cikin π-band.
Wannan yanayin yana da goyan bayan siginar binciken famfo ta hanyar amfani da na'urar bincike ta WS2 valence band a cikin lanƙwasa ta 4 na Hoto na 3. An samo waɗannan bayanai ta hanyar haɗa ƙirgawa a kan yankin da akwatin baƙar fata ya bayar a cikin Hoto na 1B wanda ke ɗaukar electrons ɗin da aka fitar daga band ɗin valence a duk jinkirin binciken famfo. A cikin sandunan kuskuren gwaji, ba mu sami wata alama ta kasancewar ramuka a cikin band ɗin valence na WS2 don kowane jinkirin binciken famfo ba. Wannan yana nuna cewa, bayan fitowar hoto, ana sake cika waɗannan ramuka cikin sauri akan sikelin lokaci kaɗan idan aka kwatanta da ƙudurin lokaci namu.
Domin samar da hujja ta ƙarshe ga hasashenmu na rabuwar caji mai sauri a cikin tsarin WS2/graphene heterostructure, mun ƙayyade adadin ramukan da aka canja zuwa layin graphene kamar yadda aka bayyana dalla-dalla a cikin Kayan Ƙarin. A takaice, rarrabawar lantarki ta wucin gadi na π-band an sanya shi da rarraba Fermi-Dirac. Sannan an ƙididdige adadin ramukan daga ƙimar da aka samu don ƙarfin sinadarai na wucin gadi da zafin lantarki. Sakamakon ya nuna a Hoto na 4. Mun gano cewa an canja jimlar adadin ramukan ~5 × 1012/cm2 daga WS2 zuwa graphene tare da tsawon rai na 1.5 ± 0.2 ps.
Canjin adadin ramuka a cikin π-band a matsayin aikin jinkirin binciken famfo tare da dacewa mai ƙarfi wanda ke haifar da tsawon rai na 1.5 ± 0.2 ps.
Daga abubuwan da aka gano a cikin Hotuna na 2 zuwa 4, hoton da ke ƙasa mai nuna ƙaramin hoto don canja wurin caji mai sauri a cikin tsarin WS2/graphene ya bayyana (Hoto na 5). Ɗaukar hoto na tsarin WS2/graphene a 2 eV ya mamaye A-exciton a cikin WS2 (Hoto na 5A). Ƙarin abubuwan motsa jiki na lantarki a fadin wurin Dirac a cikin graphene da kuma tsakanin madannin WS2 da graphene suna da yuwuwar kuzari amma ba su da inganci sosai. Raƙuman da aka ɗauka a cikin madannin valence na WS2 ana cika su da electrons waɗanda suka samo asali daga madannin graphene π akan sikelin lokaci kaɗan idan aka kwatanta da ƙudurin lokaci namu (Hoto na 5A). Electron da aka ɗauka a cikin madannin WS2 suna da tsawon rai na ~1 ps (Hoto na 5B). Duk da haka, yana ɗaukar ~2 ps don sake cika ramukan a cikin madannin graphene π (Hoto na 5B). Wannan yana nuna cewa, ban da canja wurin lantarki kai tsaye tsakanin ƙungiyar WS2 da kuma ƙungiyar graphene π, ƙarin hanyoyin shakatawa - wataƙila ta hanyar yanayin lahani (26) - suna buƙatar a yi la'akari da su don fahimtar cikakken yanayin.
(A) Hasken walƙiya a lokacin da aka kunna WS2 A-exciton a 2 eV yana saka electrons cikin ƙungiyar watsawa ta WS2. Raƙuman da suka dace a cikin ƙungiyar valence ta WS2 za a sake cika su nan take ta hanyar electrons daga ƙungiyar π-band ta graphene. (B) Masu ɗaukar hotuna a cikin ƙungiyar watsawa ta WS2 suna da tsawon rai na ∼1 ps. Raƙuman da ke cikin ƙungiyar π-band ta graphene suna rayuwa na ∼2 ps, wanda ke nuna mahimmancin ƙarin tashoshin watsawa da kibiyoyi masu lanƙwasa suka nuna. Layukan baƙi masu lanƙwasa a cikin (A) da (B) suna nuna canjin ƙungiyar da canje-canje a cikin ƙarfin sinadarai. (C) A cikin yanayin wucin gadi, ana cajin layin WS2 mara kyau yayin da layin graphene yake da caji mai kyau. Don motsawar da aka zaɓa ta juyawa tare da hasken da aka raba da zagaye, ana sa ran electrons masu ɗaukar hotuna a cikin WS2 da ramukan da suka dace a cikin graphene za su nuna bambancin juyi.
A cikin yanayin wucin gadi, electrons ɗin da aka kunna suna zaune a cikin hanyar sadarwa ta WS2 yayin da ramukan da aka kunna suna cikin hanyar sadarwa ta π ta graphene (Hoto na 5C). Wannan yana nufin cewa layin WS2 yana da caji mara kyau kuma layin graphene yana da caji mai kyau. Wannan yana lissafin canjin kololuwar wucin gadi (Hoto na 2), rashin daidaituwar siginar binciken famfo na graphene (layi na 2 da 3 na Hoto na 3), rashin ramuka a cikin hanyar sadarwa ta WS2 (layi na 4 Hoto na 3), da kuma ƙarin ramuka a cikin hanyar sadarwa ta π ta graphene (Hoto na 4). Rayuwar wannan yanayin da aka raba caji shine ∼1 ps (layi na 1 Hoto na 3).
An lura da irin waɗannan yanayi na wucin gadi da suka rabu da caji a cikin heterostructures masu alaƙa da van der Waals waɗanda aka yi daga semiconductors guda biyu kai tsaye tare da daidaitawar band na nau'i na II da kuma staggered bandgap (27-32). Bayan hasken haske, an gano cewa electrons da ramuka suna motsawa cikin sauri zuwa ƙasan band ɗin conduction da kuma saman band ɗin valence, bi da bi, waɗanda ke cikin layuka daban-daban na heterostructure (27-32).
A yanayin tsarin WS2/graphene ɗinmu, wurin da ya fi dacewa ga electrons da ramuka shine matakin Fermi a cikin layin graphene na ƙarfe. Saboda haka, mutum zai yi tsammanin cewa electrons da ramukan suna canzawa cikin sauri zuwa ga graphene π-band. Duk da haka, ma'auninmu ya nuna a fili cewa canja wurin rami (<200 fs) ya fi inganci fiye da canja wurin electron (~1 ps). Mun danganta wannan da daidaiton kuzari na WS2 da graphene bands kamar yadda aka bayyana a Hoto na 1A wanda ke ba da adadi mai yawa na yanayin ƙarshe don canja wurin rami idan aka kwatanta da canja wurin electron kamar yadda aka zata kwanan nan (14, 15). A halin yanzu, idan aka yi la'akari da ~2 eV WS2 bandgap, ƙarfin sinadaran graphene Dirac da daidaito suna kusa da ~0.5 da ~0.2 eV sama da tsakiyar bandgap na WS2, bi da bi, suna karya daidaiton electron-hole. Mun gano cewa adadin yanayin ƙarshe da ake da shi don canja wurin ramuka ya ninka sau 6 fiye da na canja wurin lantarki (duba Ƙarin Kayan Aiki), shi ya sa ake sa ran canja wurin ramuka ya fi sauri fiye da canja wurin lantarki.
Duk da haka, cikakken hoto na ƙaramin hoto na canja wurin caji mara daidaituwa da aka lura, ya kamata ya yi la'akari da haɗuwa tsakanin orbitals waɗanda suka ƙunshi aikin wave A-exciton a cikin WS2 da graphene π-band, bi da bi, hanyoyin watsa electron-electron da electron-phonon daban-daban, gami da ƙuntatawa da aka sanya ta hanyar motsi, kuzari, juyawa, da kuma kiyaye pseudospin, tasirin oscillations na plasma (33), da kuma rawar da zai iya haifar da motsawar phonon mai haɗin gwiwa wanda zai iya shiga tsakani canja wurin caji (34, 35). Hakanan, mutum zai iya yin hasashe ko yanayin canja wurin caji da aka lura ya ƙunshi excitons canja wurin caji ko nau'ikan ramuka na electron kyauta (duba Ƙarin Kayan). Ana buƙatar ƙarin bincike na ka'idoji waɗanda suka wuce iyakokin wannan takarda don fayyace waɗannan batutuwa.
A taƙaice, mun yi amfani da tr-ARPES don nazarin canja wurin caji tsakanin layukan da sauri a cikin wani tsari mai siffar WS2/graphene. Mun gano cewa, lokacin da aka yi farin ciki da amsawar A-exciton na WS2 a 2 eV, ramukan da aka yi amfani da su suna canzawa cikin sauri zuwa cikin layin graphene yayin da electrons masu ɗaukar hoto ke ci gaba da kasancewa a cikin layin WS2. Mun danganta wannan da gaskiyar cewa adadin yanayin ƙarshe da ake da su don canja wurin rami ya fi girma fiye da na canja wurin electron. An gano cewa tsawon rayuwar yanayin wucin gadi da aka raba caji ya kai ∼1 ps. Tare da haɗakar da motsin gani mai zaɓin juyawa ta amfani da hasken da aka raba da zagaye (22-25), canja wurin caji mai sauri da aka lura yana iya kasancewa tare da canja wurin juyawa. A wannan yanayin, ana iya amfani da tsarin WS2/graphene da aka bincika don ingantaccen allurar juyawa ta gani zuwa cikin graphene wanda ke haifar da sabbin na'urori na optospintronic.
An shuka samfuran graphene a kan wafers na kasuwanci mai sarrafa 6H-SiC(0001) daga SiCrystal GmbH. Wafers ɗin N-doped suna kan-axis tare da yankewa a ƙasa da 0.5°. An yi wa substrate ɗin hydrogen etched na SiC don cire ƙazanta da kuma samun lanƙwasa na yau da kullun. Daga nan aka zana saman Si-defined mai tsabta da atomically ta hanyar haɗa samfurin a cikin yanayin Ar a 1300°C na tsawon mintuna 8 (36). Ta wannan hanyar, mun sami Layer na carbon guda ɗaya inda kowace ƙwayar carbon ta uku ta samar da haɗin covalent zuwa substrate SiC (37). Daga nan aka mayar da wannan Layer zuwa graphene mai tsayin sp2-hybridized quasi free-standing hole-doped ta hanyar haɗin hydrogen (38). Ana kiran waɗannan samfuran graphene/H-SiC(0001). An gudanar da dukkan aikin a cikin ɗakin girma na Black Magic na kasuwanci daga Aixtron. An gudanar da haɓakar WS2 a cikin wani injin mai zafi na bango ta hanyar amfani da ƙaramin tururin sinadarai (39, 40) ta amfani da foda WO3 da S tare da rabon taro na 1:100 a matsayin abubuwan da suka riga suka fara aiki. An ajiye foda WO3 da S a 900 da 200°C, bi da bi. An sanya foda WO3 kusa da substrate. An yi amfani da Argon a matsayin iskar gas mai ɗaukar kaya tare da kwararar sccm 8. An riƙe matsin lamba a cikin reactor a 0.5 mbar. An siffanta samfuran da microscopy na biyu na electron, atomic force microscopy, Raman, da photoluminescence spectroscopy, da kuma ƙarancin wutar lantarki na electron diffraction. Waɗannan ma'aunai sun bayyana yankuna biyu daban-daban na WS2 guda ɗaya inda ko dai ΓK- ko ΓK'-direction an daidaita su da alkiblar ΓK na layin graphene. Tsawon gefen yanki ya bambanta tsakanin 300 zuwa 700 nm, kuma jimlar kewayen WS2 an kiyasta ya kai kusan 40%, wanda ya dace da nazarin ARPES.
An yi gwaje-gwajen ARPES masu tsauri tare da na'urar nazarin hemispherical (SPECS PHOIBOS 150) ta amfani da tsarin na'urar da aka haɗa da caji-na'urar ganowa don gano kuzarin lantarki da ƙarfin lantarki mai girma biyu. An yi amfani da hasken He Iα mara polarized, monochromatic (21.2 eV) na tushen fitarwa mai yawan kwararar iska (VG Scienta VUV5000) don duk gwaje-gwajen fitarwa na photoemission. Kuzarin kuzari da ƙudurin kusurwa a cikin gwaje-gwajenmu sun fi 30 meV da 0.3° (daidai da 0.01 Å−1), bi da bi. An gudanar da duk gwaje-gwajen a zafin ɗaki. ARPES dabara ce mai matuƙar tasiri ga saman. Don fitar da photoelectrons daga WS2 da layer graphene, an yi amfani da samfuran da ba su cika ɗaukar nauyin WS2 na ~40%.
An kafa tsarin tr-ARPES ne bisa ga na'urar ƙara ƙarfin Titanium:Sapphire mai ƙarfin 1-kHz (Coherent Legend Elite Duo). An yi amfani da ƙarfin fitarwa na 2 mJ don samar da harmonics mai yawa a cikin argon. Hasken ultraviolet mai ƙarfi da ya haifar ya ratsa ta cikin wani grating monochromator wanda ke samar da bugun bincike na 100-fs a ƙarfin photon na 26-eV. An aika da ƙarfin fitarwa na amplifier 8mJ zuwa cikin na'urar ƙara ƙarfin gani (HE-TOPAS daga Canza Haske). An ninka ƙarfin siginar a ƙarfin photon na 1-eV sau biyu a cikin lu'ulu'u na beta barium borate don samun bugun famfo na 2-eV. An yi ma'aunin tr-ARPES tare da na'urar nazarin hemispherical (SPECS PHOIBOS 100). Jimillar ƙarfin kuzari da ƙudurin lokaci shine 240 meV da 200 fs, bi da bi.
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Wannan tambayar don gwada ko kai baƙo ne na ɗan adam ko a'a, da kuma hana aika saƙonnin banza ta atomatik.
Daga Sven Aeschlimann, Antonio Rossi, Mariana Chávez-Cervantes, Razvan Krause, Benito Arnoldi, Benjamin Stadtmüller, Martin Aeschlimann, Stiven Forti, Filippo Fabbri, Camilla Coletti, Isabella Gierz
Mun bayyana rabuwar caji mai sauri a cikin tsarin WS2/graphene wanda zai iya ba da damar allurar juyawa ta gani zuwa graphene.
Daga Sven Aeschlimann, Antonio Rossi, Mariana Chávez-Cervantes, Razvan Krause, Benito Arnoldi, Benjamin Stadtmüller, Martin Aeschlimann, Stiven Forti, Filippo Fabbri, Camilla Coletti, Isabella Gierz
Mun bayyana rabuwar caji mai sauri a cikin tsarin WS2/graphene wanda zai iya ba da damar allurar juyawa ta gani zuwa graphene.
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Lokacin Saƙo: Mayu-25-2020