APL95-232101(2009)

非易失性的电阻开关在石墨烯氧化物薄膜

APPLIEDPHYSICSLETTERS95,232101 2009

Nonvolatileresistiveswitchingingrapheneoxidethin lms

C.L.He,1F.Zhuge,1X.F.Zhou,1M.Li,1G.C.Zhou,1Y.W.Liu,1J.Z.Wang,1B.Chen,1W.J.Su,1Z.P.Liu,1,a Y.H.Wu,2P.Cui,1andRun-WeiLi1,a

1

NingboInstituteofMaterialsTechnologyandEngineering(NIMTE),ChineseAcademyofSciences(CAS),Ningbo315201,People’sRepublicofChina2

DepartmentofElectricalandComputerEngineering,NationalUniversityofSingapore,Singapore117576,Singapore

Received30September2009;accepted11November2009;publishedonline7December2009 Reliableandreproducibleresistiveswitchingbehaviorswereobservedingrapheneoxide GO thin lmspreparedbythevacuum ltrationmethod.TheCu/GO/Ptstructureshowedanon/offratioofabout20,aretentiontimeofmorethan104s,andswitchingthresholdvoltagesoflessthan1V.Theswitchingeffectcouldbeunderstoodbyconsideringthedesorption/absorptionofoxygen-relatedgroupsontheGOsheetsaswellasthediffusionofthetopelectrodes.OurexperimentsindicatethatGOispotentiallyusefulforfuturenonvolatilememoryapplications.©2009AmericanInstituteofPhysics. doi:10.1063/1.3271177

Resistiverandomaccessmemory RRAM ,whichisbasedonresistanceswitchinginducedbyexternalelectricalstimulations,hasattractedgreatattentionforitspotentialap-plicationsinnextgenerationnonvolatilememoryduetoitssimplestructure,nondestructivereadout,highoperationspeed,longretentiontime,andlowpowerconsumption.Theresistiveswitchingeffecthasbeenobservedinavarietyofmaterials,includingperovskiteoxidematerials suchasPr1 xCaxMnO3 Ref.1 andCr-dopedSrZrO3 Ref.2 ,bi-narytransitionmetaloxides suchasNiO,3ZnO,4andZrO2 Ref.5 ,chalcogenides,6organicmaterials,7andamorphoussilicon.8Inlastdecades,carbon-basedmaterialshavebeenstudiedintensivelyasapotentialcandidatetoovercomethescienti candtechnologicallimitationsoftraditionalsemi-conductordevices.9–11Itisworthymentioningthatmostoftheworkoncarbon-basedelectronicdeviceshasbeenfo-cusedon eld-effecttransistors.12,13Thus,itwouldbeofgreatinterestifnonvolatilememorycanalsoberealizedincarbonsothatlogicandmemorydevicescanbeintegratedonasamecarbon-basedplatform.Herein,wereportresistiveswitchingbehaviorsinaCu/grapheneoxide GO /Ptsand-wichedstructure.Reversiblebipolarresistiveswitchingbe-haviorswereobserved.Thepossiblephysicalmechanismoftheswitchingeffectisdiscussed.

GOwithanultrathinthicknessisattractiveduetoitsuniquephysical-chemicalproperties.GOcanbereadilyob-tainedthroughoxidizinggraphiteinmixturesofstrongoxi-dants,followedbyanexfoliationprocess.Duetoitswatersolubility,GOcanbetransferredontoanysubstratesuni-formlyusingsimplemethodssuchasdrop-casting,spincoat-ing,Langmuir–Blodgettdepositionandvacuum ltration.Theas-depositedGOthin lmscanbefurtherprocessedintofunctionaldevicesusingstandardlithographyprocesseswithoutdegradingthe lmproperties.14,15Inthiswork,GOthin lmsof 30nminthicknesswerepreparedatroomtemperature RT bythevacuum ltrationmethod.FirstweobtainedGOsuspensionsthroughthesoft-chemicaldelami-nationofGOsasdescribedinRef.16.Then50gofGOsuspensionwithaconcentrationof6mg/Lwas ltered

a

throughacelluloseestermembranetoachieveuniformGOthin lms.The lmthicknesscouldbewellcontrolledbytuningtheGOconcentrationor ltrationvolume.Theas- lteredGO akeswerethentransferredfromthe ltermem-braneontocommercialPt/Ti/SiO2/Sisubstrates.Thethick-nessofGO akeswastypicallycontrolledintherangeof20–40nm.Inordertomeasuretheelectricalproperties,Cutopelectrodeswithathicknessof200nmanddiameterof100 mweredepositedatRTbyelectronbeamevaporationwithaninsitumetalshadowmask.TheI-VcharacteristicsofCu/GO/PtstructuresweremeasuredatRTbyKeithley4200semiconductorcharacterizationsystemwithvoltagesweep-ingmode.Duringthemeasurement,abiasvoltagewasap-pliedbetweenthetop Cu andbottom Pt electrodeswiththelatterbeinggrounded.TheschematicstructureofthesandwicheddevicesisdepictedinFig.1 a .

0.0100.0050.000-0.005-0.010-0.015

Current(A)

Voltage(V)

FIG.1. Coloronline a Aschematiccon gurationoftheCu/GO/Ptsand-wichedstructure. b I-VcharacteristicsoftheCu/GO/Ptstructure.Thear-rowsindicatethesweepdirection.TheinsetshowstheI-Vcharacteristicsinsemilogarithmicscale.

©2009AmericanInstituteofPhysics

Electronicaddresses:runweili@andliuzp@.

0003-6951/2009/95 23 /232101/3/$25.0095,232101-1