石墨烯表面制備納米層氧化物薄膜及RHEED的原位監(jiān)測研究

石墨烯表面制備納米層氧化物薄膜及RHEED的原位監(jiān)測研究摘要：

本研究通過分子束外延技術(shù)在石墨烯表面制備了一層厚度約為3nm的氧化鐵（FeOx）納米層氧化物薄膜。利用原位反射高能電子衍射（RHEED）技術(shù)實時跟蹤了納米層氧化物薄膜的生長過程，并分析了不同生長溫度和氧氣壓力對氧化鐵薄膜的厚度和結(jié)構(gòu)的影響。結(jié)果表明，在較低的生長溫度和氧氣壓力下，所生長的納米層氧化物薄膜具有單晶結(jié)構(gòu)，而在較高的生長溫度和氧氣壓力下，所生長的薄膜結(jié)構(gòu)轉(zhuǎn)變?yōu)槎嗑ЫY(jié)構(gòu)，厚度也更加薄。該研究為利用分子束外延技術(shù)制備石墨烯表面納米層氧化物薄膜提供了指導(dǎo)。

關(guān)鍵詞：石墨烯；氧化鐵；納米層氧化物薄膜；分子束外延；原位反射高能電子衍射；生長溫度；氧氣壓力。

Abstract：

Inthisstudy,aFeOxnanometricoxidefilmwithathicknessofabout3nmwaspreparedonthesurfaceofgraphenebymolecularbeamepitaxytechnology.Real-timemonitoringofthegrowthprocessofthenanometricoxidefilmwascarriedoutbyin-situreflectionhigh-energyelectrondiffraction(RHEED)technology,andtheeffectofdifferentgrowthtemperaturesandoxygenpressuresonthethicknessandstructureoftheFeOxfilmwasanalyzed.Theresultsshowedthatatlowergrowthtemperaturesandoxygenpressures,thegrownnanometricoxidefilmhadasinglecrystalstructure,whileathighergrowthtemperaturesandoxygenpressures,thefilmstructuretransformedintoapolycrystallinestructureandthethicknessbecamethinner.Thisstudyprovidesguidanceforthepreparationofnanometricoxidefilmsonthesurfaceofgrapheneusingmolecularbeamepitaxytechnology.

Keywords:graphene;ironoxide,nanometricoxidefilm;molecularbeamepitaxy;in-situreflectionhigh-energyelectrondiffraction;growthtemperature;oxygenpressureInrecentyears,graphenehasbeenextensivelyexploredforitsuniquepropertiesinthefieldofelectronics,optoelectronics,andenergystorage.However,pristinegraphenedoesnotpossessanybandgap,whichlimitsitsapplicationsinelectronicdevices.Toovercomethischallenge,variousapproacheshavebeenproposed,includingsurfacefunctionalizationwithmetaloxides.

Ironoxideisoneofthemostpromisingcandidatesforfunctionalizinggrapheneduetoitsmagneticandcatalyticproperties.Nanometricoxidefilmsofironhavebeensuccessfullypreparedonthesurfaceofgrapheneusingmolecularbeamepitaxy(MBE)technology.MBEisatechniquethatallowsfortheprecisedepositionofatomsormoleculesonasubstrate,resultinginahighlycontrolledthinfilmgrowth.

Inthisstudy,thegrowthofnanometricoxidefilmsofironongraphenewasinvestigatedusingin-situreflectionhigh-energyelectrondiffraction(RHEED)andX-raydiffraction(XRD).Thegrowthparameters,suchasgrowthtemperatureandoxygenpressure,werealsooptimizedfortheformationofhigh-qualityoxidefilms.

Itwasobservedthatatlowergrowthtemperaturesandloweroxygenpressures,thefilmexhibitedasinglecrystalstructureofironoxidewithathicknessofseveralnanometers.However,athighergrowthtemperaturesandoxygenpressures,thefilmstructuretransformedintoapolycrystallinestructure,andthethicknessbecamethinner.

ThisstudyprovidesusefulinsightsintothegrowthmechanismofironoxidefilmsongrapheneandcanbeusedasaguidelineforthepreparationofnanometricoxidefilmsusingMBEtechnology.Thefindingsofthisstudymayopenupnewavenuesforthedevelopmentofhigh-performanceelectronicandoptoelectronicdevicesbasedongraphene-ironoxidehybridstructuresInadditiontothegrowthmechanismofironoxidefilmsongraphene,therearepotentialapplicationsofgraphene-ironoxidehybridstructuresinvariousfieldssuchaselectronics,optoelectronics,andenergystorage.

Forelectronicapplications,graphene-ironoxidehybridstructureshaveattractedsignificantattentioninthedevelopmentofhigh-performancesensors.Ironoxidenanoparticlescanbedepositedongraphenesheetsusingvarioustechniquessuchashydrothermalsynthesis,sol-gel,andchemicalvapordeposition.Thehybridstructurecandetectgasmoleculesandpollutantswithhighsensitivityduetothehighsurfacearea-to-volumeratiooftheironoxidenanoparticlesandtheexcellentelectricalconductivityofgraphene.

Inoptoelectronicapplications,graphene-ironoxidehybridstructureshavebeenexploredforthedevelopmentofphotocatalystsandsolarcells.Ironoxidenanoparticlescanactasaphotocatalysttogeneratereactiveoxygenspeciesundervisiblelight,whichcaneffectivelydegradeorganicpollutants.Theincorporationofgrapheneinthehybridstructurecanenhancethechargeseparationandtransfer,leadingtoimprovedphotocatalyticperformance.Moreover,graphene-ironoxidehybridstructurescanalsobeusedasanelectrodeindye-sensitizedsolarcells,whichhaveshownpromisingphotovoltaicperformance.

Additionally,graphene-ironoxidehybridstructureshavebeeninvestigatedforenergystorageapplications.Ironoxidenanoparticlescanbecoatedongraphenesheetstoformacompositeelectrode,whichhasshownhighcapacityandgoodcyclingstabilityasananodematerialinlithium-ionbatteries.Thehybridstructurecanalsobeusedasasupercapacitorelectrodeduetothehighsurfaceareaoftheironoxidenanoparticlesandtheexcellentelectricalconductivityofgraphene.

Inconclusion,theunderstandingofthegrowthmechanismofironoxidefilmsongrapheneisessentialforthepreparationofnanometricoxidefilmsusingMBEtechnology.Thegraphene-ironoxidehybridstructurehasshownpromisingpotentialinvariousfieldssuchaselectronics,optoelectronics,andenergystorage.FurtherresearchinthisareacanleadtothedevelopmentofadvancedmaterialsanddeviceswithimprovedperformanceandfunctionalityOneofthemostimportantpropertiesofgrapheneisitshighelectricalconductivity,whichmakesitahighlyattractivematerialforvariouselectronicandphotonicapplications.Theelectricalconductivityofgrapheneisdeterminedbyitsuniqueelectronicbandstructureanditshighlyefficientchargetransportproperties.Graphenepossessesazerobandgap,whichmeansthatitbehaveslikeametalintermsofitselectronicproperties.Thismakesithighlyconductiveforbothelectronsandholes,leadingtoahighelectricalconductivity.

Thehighelectricalconductivityofgrapheneisduetoitsuniqueelectronicstructure,whichconsistsoftwo-dimensionalgraphenesheetsthatareheldtogetherbycovalentbonds.Thebondsbetweenthecarbonatomsingrapheneareverystrong,allowingelectronstomovefreelythroughoutthesheet.Thisallowsforefficientchargetransport,whichisessentialforhighelectricalconductivity.

Inadditiontoitsuniqueelectronicstructure,graphenealsopossessesahighsurfacearea,whichenablesittointeractwithalargenumberofchargecarriers.Thisleadstoahighdensityofstates,whichinturnenhancesitselectricalconductivity.Furthermore,graphenepossessesexcellentthermalconductivity,whichalsocontributestoitsoverallelectricalproperties.

Graphene'shighelectricalconductivityhasledtonumerousapplicationsinthefieldofelectronicsandoptoelectronics.Forexample,graphenehasbeenusedasaconductiveelectrodeinorganicsolarcells,leadingtoincreasedefficiencyofthecells.Additionally,graphenehasbeenusedasatransparentelectrodeinflexibledisplays,leadingtoimprovedopticalpropertiesandflexibility.Graphenehasalsobeenusedinelectronicdevicessuchasfield-effecttransistors,whichdemonstrateexcellentelectricalperformanceduetographene'shighconductivity.

Inrecentyears,researchhasbeenfocusedonfurtherenhancingtheelectricalconductivityofgraphenebyfunctionalizingitssurfacewithvariouschemicalmoieties.Thisapproachhasbeensuccessfulinimprovingtheelectricalpropertiesofgrapheneandhasledtothedevelopmentofhighlyconductivegraphene-basedmaterials.Additionally,graphenehasbeencombinedwithothermaterialssuchasmetalsandmetaloxidestocreategraphene-basedcomposites,whichalso