Measurement of indium concentration profiles and segregation efficiencies from high-angle annular dark field-scanning transmission electron microscopy images

We investigated segregation of indium in an InxGa1−xAs/GaAs heterostructure via high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), where contrast strongly depends on the nuclear charges of the scattering atoms (Z-contrast). Indium concentration maps have been deduc...

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Bibliographic Details
Published in:Ultramicroscopy 2013-08, Vol.131, p.1-9
Main Authors: Mehrtens, Thorsten, Müller, Knut, Schowalter, Marco, Hu, Dongzhi, Schaadt, Daniel M., Rosenauer, Andreas
Format: Article
Language:English
Subjects:
CELFA
Composition analysis
HAADF-STEM
InGaAs
Segregation
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Summary:We investigated segregation of indium in an InxGa1−xAs/GaAs heterostructure via high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), where contrast strongly depends on the nuclear charges of the scattering atoms (Z-contrast). Indium concentration maps have been deduced from HAADF-STEM images by comparing normalized measured intensities with multislice simulations in the frozen lattice approach. Segregation coefficients were derived following the segregation model of Muraki et al. [1]. This is demonstrated for HAADF-STEM images recorded in [100] and [110] zone-axes. Determined indium concentrations and segregation coefficients are compared with results from composition analysis by lattice fringe analysis (CELFA) measurements and energy-dispersive X-ray analysis (EDX). •We measured the indium concentration in an InGaAs/GaAs heterostructure by HAADF-STEM.•Multislice calculations are carried out for [100] and [110] electron beam direction.•[110] beam direction is better suited for concentration analysis.•Segregation efficiencies are derived from concentration profiles.•HAADF-STEM results are compared to CELFA measurement.
ISSN:0304-3991
1879-2723
DOI:10.1016/j.ultramic.2013.03.018