ABSTRACT
The combination of cold field-emission electron sources, improved optics, and highly sensitive CCD-detectors have pushed the limits of spatially resolved analysis into the subnanometer regime. Scanned electron probes (down to 0.3 nm diameter at 100 keV) can be used in combination with analytical techniques like Z-contrast imaging, EELS and CBED. The imaging techniques in STEM allow to resolve the crystal structure, like in TEM, directly. But, for the case of Z-contrast imaging, the results can be interpreted easily with respect to chemical composition. Additionally, quantitative measurements with EELS (e.g. for chemical analysis) and CBED (for crystal structure analysis) can be performed with the same fine probe which is used for imaging purposes. Examples for subnanometer characterization and defect recognition in III-V- and II-VI-heterostructures illustrate the capabilities of the above mentioned techniques.
