石墨烯应用研究报告

GRAPHENEFurtherApplicationsandResearchTeam#3PhillipKellerKristaMelishMichealJonesJamesKancewickIntroductionGraphene’smechanicalpropertiesGraphene’selectricalpropertiesCarbonVsSiliconSupercapacitorsandGrapheneGasDetectionusinglow-temperaturereducedgrapheneoxidesheetsUltrafastgraphenephotodetectorElectronicsandMagnetismofPatternedGrapheneNanoroadsGeneralConclusionsIntroductionAdvancesinelectronicshavebeentheresultofthecontinuousminiaturizationor‘scaling’ofelectronicdevices,particularlyofsilicon-basedtransistors,thathasledtodenser,fasterandmorepower-efficientcircuitry.Therealizationoftheapproachinglimitshasinspiredaworldwideefforttodevelopalternativedevicetechnologies.Someapproachesinvolvespin-baseddevices,whileothersreplaceakeycomponentofthedevice,theconductingchannel,withcarbonnanomaterials,whichhavesuperiorelectricalproperties.IntroductionAmongthesecarbonnanomaterialsisgraphene.Grapheneisatwodimensionalallotropeofcarbonarrangedlikeahoneycombstructuremadeoutofhexagonsandplaysanimportantrolesinceitisthebasisfortheunderstandingoftheelectronicpropertiesinotherallotropes.Wallacein1947Created2Dstructuretohelpintheunderstandingof3DGraphiteSinglelayersofgraphitegrownepitaxiallyonmetallicsubstratesinthe1970sTightlyboundtosubstrate,distortedpropertiesTerm“graphene”coinedin19872004,GeimandNovoselovmechanicallyexfoliatedsheetsofgraphenefromgraphiteTransferredtochargeneutralsiliconsubstrateFirstsuccessfulelectricalpropertiesmeasuredGeim,A.K.&MacDonald,A.H.(2007).Graphene:Exploringcarbonflatland.PhysicsToday.ACloserLookatGraphene2DhexagonalcarboncrystallatticeInfiniteboundariesActual2DstructureisdebatableGraphenesandwichThermaleffectsNaturallyoccurringMultilayeringraphiteNanospecsinsootfromexhaustCurrentlyoneofthemostresearchedmaterialsUniquephysicalandelectricalpropertiesWidearrayofpotentialusesBreakingstrength200timesgreaterthansteelYoungsmodulusof~1tPaIncrediblerigiditylendsthemselvestonanoscalepressuresensorsNanoscopicgrapheneflakesbendwithincreasingpressurewhichalterstheirelectricalconductivitywhichcanberelatedtothepressureJohnScottBunch.MechanicalandElectricalPropertiesofGraphene.CornellUniversity2008.ThermalpropertiesexceedthoseofdiamondExcellentconductorofheatPhonondominatedalthoughitcanbeshownthatatcertainconditionstheelectricalportionissignificantGrapheneElectricalPropertiesAnomalousQuantumHallEffectQuantizationoftheHalleffectDiracfermionsCarriershavezeroeffectivemassRoomtemperatureelectronmobilityof15,000cm2/V*sTheoreticallyhigherconductivityatroomtempthansilver,butunknownforcesarelimitingPossibleopticalphononscatteringfromattachedsubstrateCharlier,J.-C.,Blase,X.,&Roche,S.Electronicandtransportpropertiesofnanotubes.Rev.Mod.Phys.BothPandN-typetransistorshavebeencreatedRecentannouncementbyIBMthatgraphenetransistorwasoperatedataterahertzfrequencyTunablebandgapfrom0to0.25eVExcellentconductivitymakesgrapheneidealforelectricalleadsinsensors/capacitorsoruseintouchscreensbecauseofitsmechanicalstrengthGrapheneribbonshavetunableelectricalconductivitydependingontheshapeElectricalComponent:TransistorAtransistor'soperationspeeddependsonthesizeofthedevice—smallerdevicescanrunfaster—andthespeedatwhichelectronstravelinit.Thissizedependencehasbeenoneofthemajordrivingforcesformakingeversmallersilicontransistors.TheConsortiumofInternationalSemiconductorCompaniesinits2001InternationalTechnologyRoadmapforSemiconductorsprojectedthattransistorshavetobesmallerthan9nanometersby2016inordertocontinuetheperformancetrend.Charlier,J.-C.,Blase,X.,&Roche,S.Electronicandtransportpropertiesofnanotubes.Rev.Mod.Phys.Carbonvs.SiliconFigure(a)isIntel’s45nmsilicontransistorwhichusesaHafniunbaseddielectric.Figure(b)isawaferofthe45nmtransistorsphotographedwithadime.Theprocessorsincorporate410milliontransistorsforeachdualcorechip,and820millionforeachquadcorechip.Graphenecouldofferawayforward.Aswellasbeingextremelythinandasemiconductor,electronsmovethroughgrapheneatextremelyhighspeeds.Thecuttingedgeofsilicon-basedtransistorsisat32nanometers.Graphenehasthepotentialtofabricatetransistorsonlyafewatomsacross.Britishresearchershaveunveiledtheworld’ssmallesttransistor,whichmeasuresoneatomthickandtenatomsacross