分析电子显微镜AEM课件.ppt

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1、PartIIIAnalyticalElectronMicroscopyinMaterialsScience1.Introduction2.ImagemodeinAEM3.MicroanalysisinAEM3.1X-rayEnergyDispersiveSpectroscopy(EDS)3.2ElectronEnergyLossSpectroscopy(EELS)3.3Microdiffraction3.4Convergentbeamdiffraction1、Introduction1.Signalsgeneratedin

2、theinteractionbetweentheincidenthighenergyelectronbeamandthethincrystallinespecimen2.Howtoformaprobe3.RelationshipbetweenTEM,SEMandAEM3.1TEMImagemodeDiffractionmode3.2SEMImagemode:SE,BSE,X-RayMappingMicroanalysis:WDS,EDS3.3AEMImagingmode:TEM,STEM,SEM,Mapping(X-Ray

3、+EELS)Diffractionmode:ScanningprobeStationarydiffractionpatternMicroanalysis:EDS,EELS,micro-diffraction,convergentbeamdiffractionHowtoformaprobe?DetectorsneededforanAEM3.RelationshipbetweenTEM,SEMandAEM3.1TEMImagemodeDiffractionmode3.2SEMImagemode:SE,BSE,X-RayMap

4、pingMicroanalysis:WDS,EDS3.3AEMImagingmode:TEM,STEM,SEM,Mapping(X-Ray+EELS)Diffractionmode:ScanningprobeStationarydiffractionpatternMicroanalysis:EDS,EELS,micro-diffraction,convergentbeamdiffraction3.2SEMImagemode:SE,BSE,X-RayMappingMicroanalysis:WDS,EDSSEM二次电子像的

5、衬度——拓扑衬度3.3AEMImagingmode:TEM,STEM,SEM,Mapping(X-Ray+EELS)Diffractionmode:ScanningprobeStationarydiffractionpatternMicroanalysis:EDS,EELS,Micro-diffraction,Convergentbeamdiffraction1.BFdetectorItisplacedatthesamesiteastheapertureinBF-TEManddetectstheintensityinth

6、edirectbeamfromapointonthespecimen.2.ADFdetectorTheannulardarkfield(ADF)detectorisadiskwithaholeinitscenterwheretheBFdetectorisinstalled.TheADFdetectorusesscatteredelectronsforimageformation,similartotheDFmodeinTEM.Themeasuredcontrastmainlyresultsfromelectronsdiff

7、ractedincrystallineareasbutissuperimposedbyincoherentRutherfordscattering.3.HAADFdetectorThehigh-angleannulardarkfielddetectorisalsoadiskwithahole,butthediskdiameterandtheholearemuchlargerthanintheADFdetector.Thus,itdetectselectronsthatarescatteredtohigheranglesan

8、dalmostonlyincoherentRutherfordscatteringcontributestotheimage.Thereby,Zcontrastisachieved.2、ImaginginAEM2.1.TEM2.2.STEM-Scanningtransmissionelectronmic