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

Thorsten Mehrtens; Knut Müller; Marco Schowalter; Dongzhi Hu; Daniel M Schaadt; Andreas Rosenauer

doi:10.1016/j.ultramic.2013.03.018

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

Ultramicroscopy. 2013 Aug:131:1-9. doi: 10.1016/j.ultramic.2013.03.018. Epub 2013 Apr 6.

Authors

Thorsten Mehrtens¹, Knut Müller, Marco Schowalter, Dongzhi Hu, Daniel M Schaadt, Andreas Rosenauer

Affiliation

¹ Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany. mehrtens@ifp.uni-bremen.de

PMID: 23666109
DOI: 10.1016/j.ultramic.2013.03.018

Abstract

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.. 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).

Keywords: CELFA; Composition analysis; HAADF-STEM; InGaAs; Segregation.

Publication types

Research Support, Non-U.S. Gov't