Effect of the lower and upper interfaces on the quality of InAs/GaAs quantum dots

0431316 - FZÚ 2015 RIV NL eng J - Journal Article
Hospodková, Alice - Pangrác, Jiří - Zíková, Markéta - Oswald, Jiří - Vyskočil, Jan - Komninou, Ph. - Kioseoglou, J. - Florini, N. - Hulicius, Eduard
Effect of the lower and upper interfaces on the quality of InAs/GaAs quantum dots.
Applied Surface Science. Roč. 301, SI (2014), 173-177. ISSN 0169-4332. E-ISSN 1873-5584
R&D Projects: GA ČR GA13-15286S; GA MŠMT(CZ) LM2011026; GA MŠMT 7AMB12GR034
Institutional support: RVO:68378271
Keywords : quantum dots * InAs * GaAs * GaAsSb * reflectance anisotropy spectroscopy
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.711, year: 2014

The aim of this work is to influence QD formation by improving the lower and upper InAs/GaAs QD interface quality. Lower interface: a good epitaxial surface planarity is required for QD formation with high QD density and narrow size distribution. We demonstrate the improvement of the QD size distribution and homogeneity, when the growth rate of the buffer layer was decreased. Upper interface formed during the covering process: InAs quantum dots were capped by GaAs or by GaAsSb. The presence of Sb atoms in covering layer strongly influences the interface abruptness. In the case of GaAs covering layer, an InGaAs layer with gradual decrease of In concentration is unintentionally formed at the interface between InAs and GaAs. The presence of Sb in GaAsSb covering layer helps to form abrupt interface between InAs and covering layer. An optimal GaAsSb composition profile is suggested to prevent dissolution of QDs during the covering process and to minimize the amount of surfacting In atoms.
Permanent Link: http://hdl.handle.net/11104/0235894