title: Quantitative chemical evaluation of dilute GaNAs using ADF STEM: avoiding surface strain induced artifacts.
abstract: The high angle annular dark field intensity (HAADF) in scanning transmission electron microscopy (STEM) can be used for a quantitative evaluation of the chemical composition in dilute GaNAs quantum wells by comparison with simulated intensities. As the scattered intensity is highly sensitive to surface strain fields originating from the quantum wells embedded in GaAs, the HAADF intensity is difficult to evaluate in a quantitative way as long as strain contrast cannot be distinguished from chemical contrast. We present a method to achieve full 2D HAADF STEM compositional mapping of GaNAs/GaAs quantum well systems by making use of information from two different camera lengths.
authors.affiliation: Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany. grieb@ifp.uni-bremen.de
authors.forename: Tim
authors.initials: T
authors.lastname: Grieb
authors.forename: Knut
authors.initials: K
authors.lastname: Müller
authors.forename: Rafael
authors.initials: R
authors.lastname: Fritz
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Grillo
authors.forename: Marco
authors.initials: M
authors.lastname: Schowalter
authors.forename: Kerstin
authors.initials: K
authors.lastname: Volz
authors.forename: Andreas
authors.initials: A
authors.lastname: Rosenauer