Simultaneous Quantification of Indium and Nitrogen Concentration in InGaNAs Using HAADF-STEM. (30th September 2014)

• Record Type: Journal Article
• Authors: Grieb, Tim; Müller, Knut; Cadel, Emmanuel; Beyer, Andreas; Schowalter, Marco; Talbot, Etienne; Volz, Kerstin; Rosenauer, Andreas
• Is Part Of: Microscopy and microanalysis. Volume 20:Number 6(2014:Dec.)
• Page Start: 1740
• Page End: 1752
• Publication Date: 2014-09-30
• Subjects: Microscopy -- Periodicals; Microchemistry -- Periodicals; 502.82
• DOI: 10.1017/S1431927614013051
• Languages: English
• ISSNs: 1431-9276

Abstract

<abstract abstract-type="normal"> <title>Abstract</title> <p>To unambiguously evaluate the indium and nitrogen concentrations in In_{<italic>x</italic>}Ga_{1−<italic>x</italic>}N_{<italic>y</italic>}As_{1−<italic>y</italic>}, 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.</p> </abstract>