Measuring composition in InGaN from HAADF-STEM images and studying the temperature dependence of Z-contrast

18th Microscopy of Semiconducting Materials Conference

物理学;材料科学

Mehrtens, T.^1 ; Schowalter, M.^1 ; Tytko, D.^2 ; Choi, P.^2 ; Raabe, D.^2 ; Hoffmann, L.^3 ; Jönen, H.^3 ; Rossow, U.^3 ; Hangleiter, A.^3 ; Rosenauer, A.^1

Institute of Solid State Physics, University of Bremen, 28359 Bremen, Germany^1

Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany^2

Institute of Applied Physics, TU Braunschweig, 38106 Braunschweig, Germany^3

关键词: Atom probe tomography;    High-angle annular dark fields;    Indium concentration;    Lattice approximations;    Multi quantum well structures;    Specimen temperature;    Specimen thickness;    Temperature dependence;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/471/1/012009/pdf
DOI  :  10.1088/1742-6596/471/1/012009

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In this contribution, the indium concentration profile of an InxGa1-xN/GaN five-fold multi quantum well structure is measured from high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) images. The results are compared with an atom probe tomography study. Indium concentrations in the range of 26 at.% to 33 at.% are measured in the centre of the quantum wells. An additional indium layer of 14 at.% has been found on top of the quantum wells. In the second part, the temperature dependence of measured intensities in GaN is investigated. Here, multislice calculations in the frozen lattice approximation are carried out in dependence of specimen thickness and compared to experimental data. An increase of intensity with specimen temperature is found.