TrulyElectroforming-FreeandLow-EnergyMemristorswithPreconditionedConductiveTunnelingPaths.Yoon,J.H.,Zhang,J.,RenX.,WangZ.,WuH.,LiZ.,BarnellM.,WuQ.,Lauhon,L.J.,XiaQ.,YangJ.J.

Caption:Theleftpanelshowscross-sectionalhighresolutionTEMimageofamemristordevicewithatopviewimageinset.TherightshowsanAPTreconstruction(50x45nm2)ofaspecimentargetingtheedgeofamemristorcrossbardevice,withyellowdotsforPd,graydotsforTa,orangedotsforTa2O5andgreendotsforAg.PdwasdepositedtoprotectTafromoxidation.ScientificAchievementAPTanalysiswasperformedonnovelelectroforming-freeandlow-energymemristordeviceswithaTa/Ta2O5:Ag/RustackedstructuretoevaluatetheconcentrationanddistributionofAgatomsintheAgdopedTa2O5activelayer.TheinterfacebetweenthetopelectrodeandAgdopedTa2O5layerwassuccessfullyanalyzed,determiningtheconcentrationofAgintheTa2O5layertobe~8%,andrevealingthatAgatomsareuniformlydistributedinregionsclosetothetopelectrodeintheOFFstate.Theseobservationssupportthatthenovelmemristordevicesareswitchedthroughconductivetunnelingpathsinsteadofthecontinuoustraditionalconductivefilaments.SignificanceAtrulyelectroforming-freedevicewithbothlowswitchingcurrentandvoltagewasproposedandexperimentallydemonstratedforthefirsttime.APTanalysiscontributedtoestablishingthenovelswitchingmechanisminvolvingconductivetunnelingpathsinsteadofcontinuousconductivefilaments.

Thelowoperatingcurrentandvoltagemakethememristorshighlycompatiblewithtwo-terminalselectors,creatinganavenuetoengineermemristorsforhigh-densityandlow-energyapplications.Substoichiometrictransitionmetaldichalcogenideshavebeenshowntosupportbothvacancymotionandmetalcationmotioninsupportofmemristiveswitching.CitationYoon,J.H.,Zhang,J.,RenX.,WangZ.,WuH.,LiZ.,BarnellM.,WuQ.,Lauhon,L.J.,XiaQ.,YangJ.J.,“TrulyElectroforming-FreeandLow-EnergyMemristorswithPreconditionedConductiveTunnelingPaths”AdvancedFunctionalMaterials,27,1702010(2017)[DOI:10.1002/adfm.201702010]