title: Nanometer-scale, quantitative composition mappings of InGaN layers from a combination of scanning transmission electron microscopy and energy dispersive x-ray spectroscopy.
abstract: Using elastic scattering theory we show that a small set of energy dispersive x-ray spectroscopy (EDX) measurements is sufficient to experimentally evaluate the scattering function of electrons in high-angle annular dark field scanning transmission microscopy (HAADF-STEM). We then demonstrate how to use this function to transform qualitative HAADF-STEM images of InGaN layers into precise, quantitative chemical maps of the indium composition. The maps obtained in this way combine the resolution of HAADF-STEM and the chemical precision of EDX. We illustrate the potential of such chemical maps by using them to investigate nanometer-scale fluctuations in the indium composition and their impact on the growth of epitaxial InGaN layers.
authors.affiliation: Georgia Institute of Technology, GT-Lorraine, Metz, France.
authors.forename: K
authors.initials: K
authors.lastname: Pantzas
authors.forename: G
authors.initials: G
authors.lastname: Patriarche
authors.forename: D
authors.initials: D
authors.lastname: Troadec
authors.forename: S
authors.initials: S
authors.lastname: Gautier
authors.forename: T
authors.initials: T
authors.lastname: Moudakir
authors.forename: S
authors.initials: S
authors.lastname: Suresh
authors.forename: L
authors.initials: L
authors.lastname: Largeau
authors.forename: O
authors.initials: O
authors.lastname: Mauguin
authors.forename: P L
authors.initials: PL
authors.lastname: Voss
authors.forename: A
authors.initials: A
authors.lastname: Ougazzaden