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Proceedings Paper

Efficient Ga(As)Sb quantum dot emission in AlGaAs by GaAs intermediate layer
Author(s): Thomas Henning Loeber; Johannes Richter; Johannes Strassner; Carina Heisel; Christina Kimmle; Henning Fouckhardt
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Paper Abstract

Ga(As)Sb quantum dots (QDs) are epitaxially grown in AlGaAs/GaAs in the Stranski-Krastanov mode. In the recent past we achieved Ga(As)Sb QDs in GaAs with an extremely high dot density of 9.8∙1010 cm-2 by optimization of growth temperature, Sb/Ga flux pressure ratio, and coverage. Additionally, the QD emission wavelength could be chosen precisely with these growth parameters in the range between 876 and 1035 nm. Here we report a photoluminescence (PL) intensity improvement for the case with AlGaAs barriers. Again growth parameters and layer composition are varied. The aluminium content is varied between 0 and 90%. Reflectance anisotropy spectroscopy (RAS) is used as insitu growth control to determine growth rate, layer thickness, and AlGaAs composition. Ga(As)Sb QDs, directly grown in AlxGa1-xAs emit no PL signal, even with a very low x ≈ 0.1. With additional around 10 nm thin GaAs intermediate layers between the Ga(As)Sb QDs and the AlGaAs barriers PL signals are detected. Samples with 4 QD layers and AlxGa1-xAs/GaAs barriers in between are grown. The thickness and composition of the barriers are changed. Depending on these values PL intensity is more than 4 times as high as in the case with simple GaAs barriers. With these results efficient Ga(As)Sb QD lasers are realized, so far only with pure GaAs barriers. Our index-guided broad area lasers operate continuous-wave (cw) @ 90 K, emit optical powers of more than 2∙50 mW and show a differential quantum efficiency of 54% with a threshold current density of 528 A/cm2.

Paper Details

Date Published: 29 March 2013
PDF: 9 pages
Proc. SPIE 8634, Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling X, 86340P (29 March 2013); doi: 10.1117/12.2003641
Show Author Affiliations
Thomas Henning Loeber, Technische Univ. Kaiserslautern (Germany)
Johannes Richter, Technische Univ. Kaiserslautern (Germany)
Johannes Strassner, Technische Univ. Kaiserslautern (Germany)
Carina Heisel, Technische Univ. Kaiserslautern (Germany)
Christina Kimmle, Technische Univ. Kaiserslautern (Germany)
Henning Fouckhardt, Technische Univ. Kaiserslautern (Germany)

Published in SPIE Proceedings Vol. 8634:
Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling X
Kurt G. Eyink; Diana L. Huffaker; Frank Szmulowicz, Editor(s)

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