MATSE 481: Electron Microscopy and Diffraction Theory
Homepage: http://kriven.mse.uiuc.edu
Catalog Description, Prerequisites and Schedule:
Theory and application of transmission electron microscopy and diffraction with emphasis on thin crystals; electron optics, interference phenomena, interpretation of images and diffraction patterns, specimen preparation, etc. Prerequisite: MATSE 305 or equivalent. Credit: 3 hours or 1 unit. 3 lecture/discussion hours per week.
Course Topics:
1. Basics of electron microscopy
Introduction to SEM and TEM
Scattering and diffraction
Elastic scattering
Inelastic scattering and beam damage
Electron sources
Optics
Lenses, apertures and resolution
The instrument and electron optics
Specimen preparation
2. Diffraction
Diffraction patterns
Thinking in reciprocal space
Diffraction from crystals
Diffraction from small volumes
Stereograms, planar and directional for general symmetry
Indexing diffraction patterns, the general method
Kikuchi diffraction
Obtaining CBED patterns
Using convergent beam techniques
3. Imaging
Imaging in the TEM
Thickness and bending effects
Dark field and weak beam techniques
4. Microchemical analysis by energy dispersive spectroscopy
X-ray spectrometry
The EDS-TEM interface
Qualitative X-ray analysis
Course Objectives:
1. To understand the principles of optics, the different types
of glass lenses and how they work, and how they can be combined
to form real and virtual images.
2. To understand the physics of different types of scattering
events, viz., elastic, plastic, coherent, incoherent, forward
and back scattering.
3. Review the dual (particle and wave) nature of electrons.
4. Review the principles of crystallography and systematic extinctions.
5. To understand how an electromagnetic lens works, the coupling
of electromagnetic lenses, and effect of lens defects.
6. The construction of an SEM, TEM and STEM, including the function
and positioning of apertures, stigmators, deflectors and detectors.
7. Know how to prepare thin TEM specimens of metals, ceramics,
polymers and combinations of them (composites), using standard
techniques.
8. To be able to take bright field, dark field, centered dark
field and weak beam images, while correcting for astigmatism.
9. To be able to take a selected area diffraction pattern (SAD),
convergent beam (CBED), Kossel-Möllenstedt patterns, as well
as Kikuchi patterns, and use the latter as guides for orientation
in reciprocal space.
10. To have some familiarity with the techniques of electron backscattered
diffraction patterns (EBPD's) or orientation imaging microscopy
(OIM) in SEM.
11. To plot and manipulate both planar and directional stereograms,
and use them to both predict, as well as to analyze, SAD or Kikuchi
patterns for any crystal system (including non-orthogonal systems
such as monoclinic and triclinic).
12. To know the method of microchemical analyses by energy dispersive
X-ray spectroscopy (EDS) and wavelength dispersive spectroscopy
(WDS). Students should be familiar with both the standard (K-factor
ratio) and standardless methods for quantitative evaluation of
elements present in a specimen.
Course Outcomes:
1. an understanding of image formation by glass and electromagnetic
lenses.
2. an understanding of the physics of scattering
3. an understanding of the construction of various types of electron
microscopes, the function of the various parts and methods of
image formation.
4. an understanding of methods of sample preparation for SEM and
TEM.
5. ability to index electron diffraction patterns and interpret
Kossel- Möllenstedt and Kikuchi patterns.
6. ability to utilize EDS and WDS results for microchemical analysis.
Assessment Tools:
1. Seven sets of homework problems were formulated by the instructor,
complemented by teams of 3-4 students each. The students prepared
questions on any topic covered or any topic that could receive
more attention for the sake of clarity. The final questions were
prepared in consultation with each team by the instructor. The
students graded each homework assignment, and explained the solution
and common mistakes before the class.
2. Subsequent, more involved and challenging homework projects
were prepared by the instructor.
3. One 1 and 1/2 to 2 hour mid-term exam and a 3-hour final exam.
4. One project (sometimes written, always oral, sometimes a poster)
was done by each student. The project was relevant to the undergraduate
student's interest or to the graduate student's research topic.