材料科学中电子显微镜的各种技术介绍课件.ppt

1、路漫漫其悠远路漫漫其悠远2022-12-14材料科学中电子显微镜材料科学中电子显微镜的各种技术介绍的各种技术介绍路漫漫其悠远路漫漫其悠远1、Introduction1.Signals generated in the interaction between the incident high energy electron beam and the thin crystalline specimen2.How to form a probe3.Relationship between TEM,SEM and AEM 3.1 TEM Image mode Diffraction mode 3.2

2、 SEM Image mode:SE,BSE,X-Ray Mapping Microanalysis:WDS,EDS 3.3 AEM Imaging mode:TEM,STEM,SEM,Mapping(X-Ray+EELS)Diffraction mode:Scanning probe Stationary diffraction pattern Microanalysis:EDS,EELS,micro-diffraction,convergent beam diffraction 路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远How to f

3、orm a probe?路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远Detectors needed for an AEM路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.Relationship between TEM,SEM and AEM 3.1 TEM Image mode Diffraction mode 3.2 SEM Image mode:SE,BSE,X-Ray Mapping Microanalysis:

4、WDS,EDS 3.3 AEM Imaging mode:TEM,STEM,SEM,Mapping(X-Ray+EELS)Diffraction mode:Scanning probe Stationary diffraction pattern Microanalysis:EDS,EELS,micro-diffraction,convergent beam diffraction路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.2 SEM Image mode:SE,BSE,X-Ray Mapping Microanalysis:WDS,EDS路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠

5、远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.3 AEM Imaging mode:TEM,STEM,SEM,Mapping(X-Ray+EELS)Diffraction mode:Scanning probe Stationary diffraction pattern Microanalysis:EDS,EELS,Micro-diffraction,Convergent beam diffraction路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路

6、漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远2、Imaging in AEM2.1.TEM2.2.STEM-Scanning transmission electron microscopy2.3.STEM/SEM imaging2.4.Signal mixing-Hybrid imaging2.5.X-Ray and EELS mapping 路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠

7、远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3、Microanalysis in AEM3.1 X-Ray quantitative microanalysis 3.1.1 X-Ray signal generation in TEM thin foil specimens 3.2.2 Identification and elimination of spurious signals 3.2.3 Optimization of the AEM for microanalysis 3.2.4

8、X-Ray microanalysis 3.2.5 Microanalysis limit3.2 EELS-Electron Energy Loss Spectroscopy 3.2.1 energy loss process in thin foil TEM specimens 3.2.2 Where to find the energy loss electrons?3.2.3 Electron energy loss spectrometer 3.2.4 Comparison of the signal generating process for EDS and EELS 3.2.5

9、The energy loss spectrum 3.2.6 EELS Microanalysis and the limit of analysis 3.2.7 Conclusion remarks 3.3 Comparison between EDS and EELS 路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远X-Ray signal generation in TEM thin foil specimensFluorescence yield(w)w):w=0 w=0 for Z 5 (Boron k shell ionization)Z 27 (Cobalt L shell)Z

10、57 (lathanlum M shell)路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.2.3 Optimization of the AEM for microanalysis3.2.4 X-Ray microanalysis路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远Cliff and Lorimer:CA+CB=100%路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远Limit for microanalysi

11、s by EDS1.Absolute accuracy 2 Minimum detectable mass:MDM 10-20g 3 Minimum mass fraction:MMF 0.1wt%4 Spatial resolution:10 20 nm5 Low Z limit6 Practical limitations:(1)contamination (2)Embedded particales 路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.2 EELS-Electron Energ

12、y Loss Spectroscopy 3.2.1 energy loss process in thin foil TEM specimens 3.2.2 Where to find the energy loss electrons?3.2.3 Electron energy loss spectrometer 3.2.4 Comparison of the signal generating process for EDS and EELS 3.2.5 The energy loss spectrum 3.2.6 EELS Microanalysis and the limit of a

13、nalysis 3.2.7 Conclusion remarks 路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.2.2 Where to find the energy loss electrons?路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远3.3.3 EELS Spectrometer路漫漫其悠远路漫漫其悠远3.2.4 Comparison of the signal generating and collection process for EDS and EELS 1.Signal generation EDS-secondary event High

14、 energy incident electrons excitation of atoms characteristic X-rays or Auger electrons EELS-primary event2.Collection efficiency EDS-very low!X-Ray generation:for carbon:1 in every 400 k-shell ionization for Na,1 in 40 Collection efficiency:WDS:10-3-10-4 EDS:10-2 Gold layer(20nm):only allow 67%be t

15、ransmitted!The Dead layer below the gold layer:37%of the 67%be transmitted!EELS:very high!75%of the energy loss electrons with a collection angle of 10 mrad 100%when collection angle is 30 mrad路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远 3.2.5 The energy loss spectrum(1)The zero loss peak(2)The low loss region of the s

16、pectrum DE=50eV energy loss peak-ionization edges pre-edge and post-edge structure路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远Microanalysis using ionization peaks(edges)路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路

17、漫漫其悠远路漫漫其悠远路漫漫其悠远3.2.5 The limitations in EELS analysis1.Detection limits MDM:In 500 Fe foil,103 atoms for Li and Al 3 x 104 atoms for O(k-edge)MDF:C in 300 steel:3at%(100 atoms)O in 600 steel:6at%2.Specimen thickness3.Spatial resolution路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫

18、其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远Phase identification路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远4、Micro Diffraction4.1 Limit of the Selected area electron diffraction(SAD)4.2 Micro diffraction 4.2.1 the Ricke method 4.2.2 convergent beam micro diffraction 路漫漫其悠远路漫漫其悠远4.1

19、 Limit of the Selected area electron diffraction(SAD)路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5、Convergent beam diffraction5.1 Terminology5.2 How to get a CBDP5.3 ZOLZ-the Zero Order Laue Zone5.4 Thickness Measurement by CBDP5.5 HOLZ-Higher Order Laue Zone5

20、.6 HOLZ Lines-Higher Order Laue Zone Lines5.7 ZAPS-the zone Axis Patters5.8 Acquiring 3-D symmetry information5.9 Phase identification5.10 summary 路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.1 TerminologyZOLZ-Zero Order Laue ZoneHOLZ-Higher Order Laue ZoneFOLZ-First Order Laue ZoneSOLZ-Second Order Laue ZoneKikuchi L

21、inesHOLZ LinesDynamical EffectK-M PatternKossel Pattern路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.2 How to get a CBDP路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.3 ZOLZ-the Zero Order Laue Zone路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.4 Thickness Measurement by CBDP路漫漫其悠远路漫漫其悠远路漫

22、漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.5 HOLZ-Higher Order Laue Zone5.5.1 Higher order Laue zone5.5.2 Determination of interplanar spacings parallel to the electron beam direction5.5.3 Indexing of the HOLZ maxima hu+kv+lw=1 for FOLZ maxima hu+kv+lw=2 for SOLZ maxima路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远F

23、or fcc:When U+V+W oddWhen U+V+W evenFor bcc:When UVW all oddWhen UVW all evenFor Hex crystal:路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.6 HOLZ Lines-Higher Order Laue Zone Lines5.6.1 HOLZ lines5.6.2 Indexing of HOLZ lines5.6.3 Application of HOLZ lines Unit cell dimension Crystal symmetry Crystal defect路漫漫其悠远路漫漫其悠远路

24、漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.7 ZAPS-the zone Axis Patters5.8 Acquiring 3-D symmetry informationFrom Kossel patternFrom K-M pattern For SAD:32 point groups are reduced to 11 projected diffraction groups For CBED:There are 31 diffraction groups w

25、hich corresponds to 32 point groups 230 space groups can be deduced from point group and the element of micro symmetry-screw axis and glide plane路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远5.9 Phase identification路漫漫其悠远路漫漫其悠远路漫漫其悠远路漫漫其悠远s-phase路漫漫其悠远路漫漫其悠远