SCANNING ELECTRON MICROSCOPY METHODS
IN STUDY OF MICRO OBJECTS
PROJECT SUPERVISOR: Prof Oleg Orelovitch
STUDENTS: Matiwane Aphiwe
Madito Jack
Masikhwa Tshifhiwa
Takata Nwabisa
FLEROV LABORATORY OF NUCLEAR REACTIONS
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Outline
• Introduction
• Principle of Scanning Electron Microscope
• Components of the instrument
• Types of SEM specimens
• Specimen preparation for SEM analysis
• Results
• Conclusion
• Acknowledgements and References
3
Introduction
• What is SEM?
– It is a linear accelerator of electrons in which the surface
of a specimen is scanned by beam of electrons that are
reflected to form an image.
• What can be studied in SEM?
– Topography and morphology
– Chemistry
– Crystallography
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Introduction cont.
http://www.ufrgs.br/imunovet/molecular_immunology/microscopy.html accessed: 2015-09-18
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Introduction cont.
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Electric states info. Atomic number differences
Specimen bulk
Thic
kness d
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Excitation v
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Cathodoluminescence (CL)Backscattered electrons (BE) Topographical info.
Secondary electrons (SE)
Thickness composition inf.
Specimen surface
Insulator charging.
Auger electrons (AE)Surface composition
Characteristic X-ray (EDX)
Continuum X-ray
Incident electron beam
http://www.ufrgs.br/imunovet/molecular_immunology/microscopy.html accessed: 2015-09-18
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Introduction cont.
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Signal amplifier
WDS
EDS
SE detector
Specimen chamber
Ele
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V-light Microscope
BE detector
http://serc.carleton.edu/research_education/geochemsheets/techniques/EPMA.html accessed: 2015-09-18
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Types of SEM specimens
• Organic and Inorganic materials:
– Polymers
– Biological samples
– Liquid samples
• Metallic samples, etc.
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Specimen preparation for SEM analysis
• SEM
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30B
Ion sputter
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Specimen stage
Silver paste
Carbon tape
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Ion sputter
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SEM systems
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Tabletop Scanning Microscope TM3000A
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Tungsten Cathode Scanning Microscope S-3400N (3 nm)C With Analytical attachments
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30B High-resolution Scanning Field Emission Microscope SU8020 (1 nm)
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SEM Results
• Contrast from elements with different atomic numbers
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Cu
Z=29
Au
Z=79
C
Z=6
Bronze
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SEM Results cont.
• Thin films (Polymer)
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Uncoated
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Au coatedB
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SEM Results cont.
• Thin films (Polymer)
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Low magnification
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High magnificationB
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SEM Results cont.
• Tabletop microscope: Powder samples (Tungsten sulfide)
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SEM Results cont.
• High-resolution microscope: Powder samples (Tungsten sulfide)
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44.1 nm
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Inte
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Energy(KeV)
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SEM Results cont.
• Tabletop microscope: Powder samples (Vanadium sulfide)
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SEM Results cont.
• Powder samples (Activated Carbon)
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SEM Results cont.
• Powder samples (Activated Carbon)
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Conclusion
• Principle of scanning electron microscope and components of the
instrument were learned.
• Thin polymer samples and powder samples were prepared for SEM
analysis.
• Tabletop and high-resolution microscopes capabilities/similarities
were investigated and it can be concluded that high-resolution
microscope gives detailed analyses of the specimen due to
integrated components of the system.
• A learning phase of the basic use of SEM in research was carried-
out successfully.
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Acknowledgements
Prof. Oleg Orelovitch
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References
• Echlin, P. (2009), Handbook of sample preparation for scanning
electron microscopy and x-ray microanalysis, Ed 1, Springer US, pg.
94-97,
• Goldstein, J. (2003) Scanning electron microscopy and x-ray
microanalysis. Kluwer Academic/Plenum Publishers, p. 689
• Reimer, L. (1998) Scanning electron microscopy : physics of image
formation and microanalysis. Springer, p. 527
• Clarke, A. R. (2002) Microscopy techniques for materials science. CRC
Press (electronic resource)
21 Thank you for your attention!
