Atomic-column scanning transmission electron microscopy analysis of misfit dislocations in GaSb/GaAs quantum dots

Fernández-Delgado, N. and Herrera, M. and Chisholm, M. F. and Ahmad Kamarudin, Mazliana and Zhuang, Qiandong and Hayne, Manus and Molina, S. I. (2016) Atomic-column scanning transmission electron microscopy analysis of misfit dislocations in GaSb/GaAs quantum dots. Journal of Materials Science, 51 (16). pp. 7691-7698. ISSN 0022-2461

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Abstract

The structural quality of GaSb/GaAs quantum dots (QDs) has been analyzed at atomic scale by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy. In particular, we have studied the misfit dislocations that appear because of the high lattice mismatch in the heterostructure. Our results have shown the formation of Lomer dislocations at the interface between the GaSb QDs and the GaAs substrate, but also at the interface with the GaAs capping layer, which is not a frequent observation. The analysis of these dislocations point to the existence of chains of dislocation loops around the QDs. The dislocation core of the observed defects has been characterized, showing that they are reconstructed Lomer dislocations, which have less distortion at the dislocation core in comparison to unreconstructed ones. Strain measurements using geometric phase analysis (GPA) show that these dislocations may not fully relax the strain due to the lattice mismatch in the GaSb QDs.

Item Type: Journal Article
Journal or Publication Title: Journal of Materials Science
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/2200/2210
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 79778
Deposited By: ep_importer_pure
Deposited On: 31 May 2016 12:08
Refereed?: Yes
Published?: Published
Last Modified: 21 Oct 2019 00:43
URI: https://eprints.lancs.ac.uk/id/eprint/79778

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