Honeycomb Carbon A Review of Graphene 石墨烯综述(18)

纳米材料在生物医学中的应用

142ChemicalReviews,2010,Vol.110,No.1Allenet

al.

Figure17.Polyacyclicaromatichydrocarbons(PAHs)mayofferaground-upsynthesisofgraphene.(a)ChemicalstructureofPAHsand(b)TEMofananoribbonsynthesizedbyMullen.(Reprintedwithpermissionfromref35.Copyright2008AmericanChemicalSociety.)

theymayindeedexhibitgraphene-likebehavior.Ifresearch-ersinthisareaareabletofurtherextendthesizerangeofPAHsinthecomingyears,thiscouldprovideacleansyntheticroutetographeneforsomeapplications.Inanyevent,theorganictechniquesdevelopedwillhaveimportantimplicationsformodi cationoforadditiontoconjugatedcarbonmacromolecules.

5.3.EpitaxialGrapheneandChemicalVaporDeposition

Whilesolution-basedsyntheticschemesaimtocircumventtheneedforsupportsubstrates,twotechniquestakeadvan-tageofspeciallychosenplatformstoencouragegrowthofhighqualitygraphene.

DeHeerandothersattheGeorgiaInstituteofTechnologypioneeredanepitaxialmethodinwhichgrapheneresultsfromthehightemperaturereductionofsiliconcarbide(seeFigure18).38-40,118-120Theprocessisrelativelystraightforward,assilicondesorbsaround1000°Cinultrahighvacuum.Thisleavesbehindsmallislandsofgraphitizedcarbon,whichwere rstlocatedbySTMandelectrondiffractionexperiments.Morerecently,groupshaveusedphotolithographytopatternepitaxialgrowthinpredeterminedlocationsandtomakedevices.119

Anumberofphysicalpropertiesdifferbetweenepitaxiallygrownandmechanicallyexfoliatedgraphene.37,39Thisisduetothein uenceofinterfacialeffectsinepitaxialgraphene,whichareheavilydependentonboththesiliconcarbidesubstrateandseveralgrowthparameters.Forepitaxialgraphene,differencesintheperiodicityobservedbySTMandLEEDSarenotwellunderstood.121Thesameistruefor

搜索“diyifanwen.net”或“第一范文网”即可找到本站免费阅读全部范文。收藏本站方便下次阅读，第一范文网，提供最新教学研究Honeycomb Carbon A Review of Graphene 石墨烯综述(18)全文阅读和word下载服务。