1. Electron Microcopy 180/198-334 Useful info – many websites. Images here from www.microscopy.ethz.ch/elmi-home.htm

2. De Brogle wavelength of electrons 100 KeV electron has 3.7 pm wavelength!

3. Electron-matter interactions

4. EDXS spectrum

5. Elastic interactions No energy is transferred from the electron to the sample. The electron either passes without any interaction (direct beam) or is scattered by the positive potential inside the electron cloud. These signals are mainly exploited in TEM and electron diffraction.

6. Inelastic Interactions Energy is transferred from the incident electrons to the sample: secondary electrons, phonons, UV quanta or cathodoluminescence are produced; shooting out inner shell electrons leads to the emission of X-rays or Auger electrons. These signals are used in analytical electron microscopy. Excellent manuscript: www.microscopy.ethz.ch/downloads/Interactions.pdf

7. Interaction volumes

8. Energy dependence

9. Energy dependence II

10. Some SEM images

11. Backscattered electrons Material contrast

12. Basic TEM and SEM

13. Which EM to use? The method that is needed is determined by the question to be solved: Structure (High-Resolution) Transmission Electron Microscopy Scanning Transmission Electron Microscopy (STEM) Electron diffraction (ED) Composition Energy-dispersive X-ray spectroscopy (EDXS) Electron Energy Loss Spectroscopy (EELS) Morphology Scanning Electron Microscopy (SEM) Elemental mapping Electron Spectroscopic Imaging (ESI) STEM + X-ray spectroscopy / EELS SEM + X-ray spectroscopy

14. De Brogle wavelength of electrons 100 KeV electron has 3.7 pm wavelength! Is this the limit?

15. Scattering and diffraction Experiment Basic structures and how to label them X-ray diffraction

16. Experiment

17. Bragg’s Law constructive interference destructive interference of waves

18. Crystal symmetries: finite number! 7 crystal systems: The crystal systems are a grouping of crystal structures according to the axial system used to describe their lattice. Each crystal system consists of a set of three axes in a particular geometrical arrangement. Cubic, hexagonal, tetragonal, rhombohedral (also known as trigonal) orthorhombic, monoclinic and triclinic. 14 Bravais lattices: When the crystal systems are combined with the various possible lattice centerings, we arrive at the Bravais lattices. They describe the geometric arrangement of the lattice points, and thereby the translational symmetry of the crystal.

19. Unit cells of a cubic crystal 3 different Bravais lattices

20. Directions in a cubic crystal

21. Miller indices of crystal planes

22. Examples of low index planes

23. Important results for cubic systems