最新X-ray Photoelectron Spectroscopy (XPS)教学讲义ppt课件.ppt

《最新X-ray Photoelectron Spectroscopy (XPS)教学讲义ppt课件.ppt》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、X-rayPhotoelectronSpectroscopy(XPS)SurfaceAnalysisTheStudyoftheOuter-MostLayersofMaterials(<100).ElectronSpectroscopiesXPS:X-rayPhotoelectronSpectroscopyAES:AugerElectronSpectroscopyEELS:ElectronEnergyLossSpectroscopyIonSpectroscopiesSIMS:SecondaryIonMass

2、SpectrometrySNMS:SputteredNeutralMassSpectrometryISS:IonScatteringSpectroscopyIntroductiontoX-rayPhotoelectronSpectroscopy(XPS)X-rayPhotoelectronSpectroscopySmallAreaDetectionX-rayBeamX-raypenetrationdepth~1mm.Electronscanbeexcitedinthisentirevolume.X-ray

3、excitationarea~1x1cm2.ElectronsareemittedfromthisentireareaElectronsareextractedonlyfromanarrowsolidangle.1mm210nmXPSspectrallinesareidentifiedbytheshellfromwhichtheelectronwasejected(1s,2s,2p,etc.).Theejectedphotoelectronhaskineticenergy:KE=hv-BE-Followi

4、ngthisprocess,theatomwillreleaseenergybytheemissionofanAugerElectron.ConductionBandValenceBandL2,L3L1KFermiLevelFreeElectronLevelIncidentX-rayEjectedPhotoelectron1s2s2pThePhotoelectricProcessLelectronfallstofillcorelevelvacancy(step1).KLLAugerelectronemitt

5、edtoconserveenergyreleasedinstep1.ThekineticenergyoftheemittedAugerelectronis:KE=E(K)-E(L2)-E(L3).ConductionBandValenceBandL2,L3L1KFermiLevelFreeElectronLevelEmittedAugerElectron1s2s2pAugerRelationofCoreHoleXPSEnergyScaleTheXPSinstrumentmeasuresthekinetice

6、nergyofallcollectedelectrons.TheelectronsignalincludescontributionsfrombothphotoelectronandAugerelectronlines.KE=hv-BE-specWhere:BE=ElectronBindingEnergyKE=ElectronKineticEnergyspec=SpectrometerWorkFunctionPhotoelectronlineenergies:Dependentonphotonenerg

7、y.Augerelectronlineenergies:NotDependentonphotonenergy.IfXPSspectrawerepresentedonakineticenergyscale,onewouldneedtoknowtheX-raysourceenergyusedtocollectthedatainordertocomparethechemicalstatesinthesamplewithdatacollectedusinganothersource.XPSEnergyScale-K

8、ineticenergyXPSEnergyScale-BindingenergyBE=hv-KE-specWhere:BE=ElectronBindingEnergyKE=ElectronKineticEnergyspec=SpectrometerWorkFunctionPhotoelectronlineenergies:NotDependentonphotonenergy.Augerelectronline