Morphology and valence band offset of GaSb quantum dots grown on GaP(001) and their evolution upon capping

This work presents a detailed study of GaSb quantum dot (QD) epitaxy on (001) GaP substrates by means of molecular beam epitaxy. Despite the large mismatch between GaP and GaSb, we show that in the nucleation-diffusion regime, the QD size distribution follows the predictions of the scaling theory. S...

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Bibliographic Details
Published in:Nanotechnology 2017-06, Vol.28 (22), p.225601
Main Authors: Desplanque, Ludovic, Coinon, Christophe, Troadec, David, Ruterana, Pierre, Patriarche, Gilles, Bonato, Leo, Bimberg, Dieter, Wallart, Xavier
Format: Article
Language:English
Subjects:
Chemical Sciences
Cristallography
Material chemistry
molecular beam epitaxy
nanoflash memories
Physics
quantum dots
scaling theory
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Summary:This work presents a detailed study of GaSb quantum dot (QD) epitaxy on (001) GaP substrates by means of molecular beam epitaxy. Despite the large mismatch between GaP and GaSb, we show that in the nucleation-diffusion regime, the QD size distribution follows the predictions of the scaling theory. Scanning transmission electron microscopy analysis of grown QDs reveal that they are plastically relaxed by 60° pairs of misfit dislocations and the valence band offset measured by x-ray photoelectron spectroscopy on such QDs amounts to 0.5 eV. After capping, the QD morphology is strongly modified with a large P/Sb exchange-segregation reaction, which even leads to the formation of core-shell nanostructures. Remarkably the resulting QD layer is coherent to the substrate without any remaining misfit dislocation and exhibits still strong composition modulations.
ISSN:0957-4484
1361-6528
DOI:10.1088/1361-6528/aa6f41