Materials Sciences and Engineering 571

Course Description

Electron microscopy students will learn to operate an electron microsope; they will study kinematical and dynamical diffraction theory; structure determination and will analyze lattice defects.

Course Outline

1. Introducing the TEM. Revision of basic crystallography
2. Electron scattering by atoms, unit cells, crystals. Bragg's law
3. The Ewald sphere construction. Constructing and interpreting electron diffraction patterns. Crystal shape effects.
4. The fresnal construction and image intensities.
5. The Kinematic theory of diffraction imaging. Bend contours and thickness fringes.
6. Dislocation and stacking faults. Images of imperfect crystals. Visibility criterion.
7. Problems with the Kinematic theory.
8. Multiple scattering - the Dynamical theory.
9. Electron absorption and its effects on dynamical theory.
10. Bloch waves. Dynamical theory and Schrodinger's equation.
    1. The optics of the TEM
    2. Electron guns, electron lenses, vacuum systems.
    3. Sample preparation for the TEM.
    4. Inelastic electron scattering - EELS and microanalysis
    5. Fluorescent Xray production. ALCHEMI effects
    6. The resolution limit of the TEM. The Contrast Transfer Function and the idea of phase imaging in the TEM.
    7. Lattice imaging, structure imaging
    8. Electron holography.

In the laboratory sessions you will learn how to align and run the TEM and take electron diffraction patterns and micrographs. You will both observe ready-made samples and practice sample preparation on selected specimens. By Spring Break you will have started on your Class Project. Your grade is determined from class assignments (40%), lab notebooks (25%), and project write-up (35%). There are no scheduled exams and no textbook is required.