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Proceedings Paper

Highly ordered Ga(As)Sb quantum dots grown on pre-structured GaAs
Author(s): Thomas Henning Loeber; Johannes Strassner; Sandra Wolff; Bert Laegel; Henning Foukhardt
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Paper Abstract

Ga(Sb)As quantum dots (QDs) are usually grown on plane GaAs substrates by self-organization in the StranskiKrastanov mode. Here we report on Ga(As)Sb QD growth on a pre-structured GaAs substrate to achieve highly ordered QDs. The structure consists of a two-dimensional array of holes/troughs milled into the substrate (wafer with initial epitaxial buffer layer) with a gallium focused ion beam (Ga-FIB). Thus, the area density of the QDs can be controled. For exact positioning of the QDs in the milled holes it is important that the diameter of the dots equals the diameter of the milled holes. In a previous publication we have shown that we are able to change the diameter as well as the height of the QDs by controlled variation of growth temperature, Ga/Sb ratio, and nominal coverage. The diameter and depth of the milled holes as well as their separation are varied. Also, different milling techniques are examined to optimize milling time and procedure. The pre-structured GaAs substrate is overgrown in a second molecular-beam-epitaxial (MBE) step, first with another thin GaAs buffer layer, then with a QD layer. With the optimum of the milling and growth parameter sets the diameter of the QDs equals the size of the milled holes and the QDs can be grown highly ordered in the given pre-structured array. To the best of our knowledge this is the first report about exact positioning of Ga(As)Sb QDs on GaAs.

Paper Details

Date Published: 20 February 2017
PDF: 8 pages
Proc. SPIE 10114, Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XIV, 101140P (20 February 2017); doi: 10.1117/12.2252221
Show Author Affiliations
Thomas Henning Loeber, Technische Univ. Kaiserslautern (Germany)
Johannes Strassner, Technische Univ. Kaiserslautern (Germany)
Sandra Wolff, Technische Univ. Kaiserslautern (Germany)
Bert Laegel, Technische Univ. Kaiserslautern (Germany)
Henning Foukhardt, Technische Univ. Kaiserslautern (Germany)

Published in SPIE Proceedings Vol. 10114:
Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XIV
Diana L. Huffaker; Holger Eisele, Editor(s)

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