Atomic-Resolution Chemical Analysis at 100 Kv in the Scanning Transmission Electron Microscope

ABSTRACTIn a 100 kV VG HB501 UX dedicated scanning transmission electron microscope, the 2.2 Å probe size allows the atomic structure to be observed with compositional sensitivity in the Z-contrast image. As this image requires only the high-angle scattering, it can be used to position the probe for simultaneous electron energy loss spectroscopy. Energy loss signals in the core loss region of the spectrum (>300 eV) are sufficiently localized that the spatial resolution is limited only by the probe. The electronic structure of the material at the interface can thus be determined on the same scale as the changes in composition, and atomic structure can be observed in the image, allowing the structure and chemical bonding at interfaces and boundaries to be characterized at the atomic level.