Interface location by depth sectioning using a low-angle annular dark field detector

Gary Ruben, E C Cosgriff, Adrian J D'Alfonso, Scott Findlay, James M LeBeau, Leslie J Allen

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    Abstract

    We investigate the application of a highly convergent aberration-corrected electron probe to the determination of depth-related features of layered heterostructures. By centring the probe upon an atomic column and varying defocus, we obtain a depth-scan of the signal from a low-angle annular dark field (LAADF) detector. Peaks associated with the heterojunctions and crystal surfaces are observed which allow for the sample thickness and heterojunction locations to be determined. Channelling of the electron wave function along atomic columns is shown to play an important role in the production of these peaks, whose presence at all interfaces is shown to rely on a combination of elastic and thermal diffuse scattering signals.
    Original languageEnglish
    Pages (from-to)131-138
    Number of pages8
    JournalUltramicroscopy
    Volume113
    Issue number1
    DOIs
    Publication statusPublished - 2012

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