title: Simultaneous quantification of indium and nitrogen concentration in InGaNAs using HAADF-STEM.
abstract: To unambiguously evaluate the indium and nitrogen concentrations in In(x)Ga(1-x)N(y)As(1-y), two independent sources of information must be obtained experimentally. Based on high-resolution scanning transmission electron microscopy (STEM) images taken with a high-angle annular dark-field (HAADF) detector the strain state of the InGaNAs quantum well is determined as well as its characteristic HAADF-scattering intensity. The strain state is evaluated by applying elasticity theory and the HAADF intensity is used for a comparison with multislice simulations. The combination of both allows for determination of the chemical composition where the results are in accordance with X-ray diffraction measurements, three-dimensional atom probe tomography, and further transmission electron microscopy analysis. The HAADF-STEM evaluation was used to investigate the influence of As-stabilized annealing on the InGaNAs/GaAs sample. Photoluminescence measurements show an annealing-induced blue shift of the emission wavelength. The chemical analysis precludes an elemental diffusion as origin of the energy shift--instead the results are in agreement with a model based on an annealing-induced redistribution of the atomic next-neighbor configuration.
authors.affiliation: 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Grieb
authors.affiliation: 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany.
authors.forename: Knut
authors.initials: K
authors.lastname: Müller
authors.affiliation: 2Groupe de Physique des Matériaux (GPM) UMR 6634,Normandie Université,Université et INSA de RouenCNRS,Av. de l'Université,BP 12,76801 Saint Etienne du Rouvray,France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cadel
authors.affiliation: 3Materials Science Center and Faculty of Physics,Philipps University Marburg,Hans Meerwein Straße,35032 Marburg,Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Beyer
authors.affiliation: 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Schowalter
authors.affiliation: 2Groupe de Physique des Matériaux (GPM) UMR 6634,Normandie Université,Université et INSA de RouenCNRS,Av. de l'Université,BP 12,76801 Saint Etienne du Rouvray,France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Talbot
authors.affiliation: 3Materials Science Center and Faculty of Physics,Philipps University Marburg,Hans Meerwein Straße,35032 Marburg,Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Volz
authors.affiliation: 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rosenauer