Scanning Transmission Electron Microscopy: Applications in Materials Science

Various Scanning Transmission Electron Microscopy (STEM) imaging techniques (ADF, HAADF, ABF) have become extremely useful for materials characterization at the nano- and atomic scale, particularly due to recent developments in the correction of spherical aberrations (Cs) of the (S)TEM¢s microscope lenses. The main principle underpinning these imaging techniques is that the detectors are designed such that they mostly collect high-angle scattered electrons, thus minimizing the contribution of elastically scattered electrons to the image. As a consequence, the intensity of the atom columns can be correlated to the chemical composition, or in case of annular bright-field STEM imaging, the light elements can be observed. This lecture will present an overview on the basic principles of STEM imaging techniques. The results of qualitative and quantitative STEM imaging at the nano- and atomic scale will be presented and commented on for various oxide ceramic materials. Selected results from probe Cs-corrected (S)TEM will also be presented.