Microanalysis at atomic resolution

In this paper the authors discuss how the dedicated scanning transmission electron microscope can provide a microanalysis of crystalline materials at atomic resolution. The method requires the establishment of incoherent conditions for a reference imaging signal as well as the spectroscopic signal. The image can then be used to focus and locate the probe to atomic precision for microanalysis. The Z-contrast image provides the most convenient incoherent reference image, and X-ray and electron energy loss data may be acquired simultaneously. In zone axis crystals, strong columnar channeling delays the onset of beam broadening for several hundred Angstroms, so that atomic resolution microanalysis may be achieved in materials specimens of significant thickness. This combination of signals provides a powerful means for studying interface structure and bonding, and avoids relying on preconceived model structures