title: Quantitative composition determination at the atomic level using model-based high-angle annular dark field scanning transmission electron microscopy.
abstract: High angle annular dark field scanning transmission electron microscopy (HAADF STEM) images provide sample information which is sensitive to the chemical composition. The image intensities indeed scale with the mean atomic number Z. To some extent, chemically different atomic column types can therefore be visually distinguished. However, in order to quantify the atomic column composition with high accuracy and precision, model-based methods are necessary. Therefore, an empirical incoherent parametric imaging model can be used of which the unknown parameters are determined using statistical parameter estimation theory (Van Aert et al., 2009, [1]). In this paper, it will be shown how this method can be combined with frozen lattice multislice simulations in order to evolve from a relative toward an absolute quantification of the composition of single atomic columns with mixed atom types. Furthermore, the validity of the model assumptions are explored and discussed.
authors.affiliation: Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020 Antwerp, Belgium. Electronic address: gerardo.martinez@uantwerpen.be.
authors.forename: G T
authors.initials: GT
authors.lastname: Martinez
authors.affiliation: Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Alle 1, D-28359 Bremen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Rosenauer
authors.affiliation: Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: De Backer
authors.affiliation: Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Verbeeck
authors.affiliation: Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Van Aert
keywords: Composition determination; HAADF STEM; STEM simulations; Statistical parameter estimation theory