Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 14: Poster II

HL 14.9: Poster

Monday, March 18, 2024, 15:00–18:00, Poster F

Investigation of Temperature Dependent Intensity Anomalies of Local Droplet Etched Gallium-Arsenide Quantum Dots — •Sayed Shkeebullah Sadat, Hans-Georg Babin, Andreas Wieck, and Arne Ludwig — Ruhr-Universität Bochum, Bochum, Deutschland

Liquid droplet etched (LDE) quantum dots (QD) made with molecular beam epitaxy (MBE) show an interesting behavior when photoluminescence (PL) spectroscopy is performed: during the growth process of the QDs an AlAs-wall can emerge around the nanoholes, which acts as a potential barrier between the QDs and the surrounding wetting layer (WL). By temperature- and power-dependent measurements anomalous behavior of photoluminescence intensity can be observed * in the here measured range of 83K-283K the intensity increases significantly to a certain sweetspot-temperature, before decreasing due to thermally activated non-radiative recombination. This initial behavior can be explained by an increase of available charged carriers from the WL with increasing temperature. Here not only the generation and recombination of excitons play an important role, but specifically the influence of temperature on thermally activated and assisted processes such as overcoming the barrier between WL and QDs and tunneling through the barrier. As part of this work a rate equation is developed, which considers the different thermal dependencies and thus should provide a quantitative insight into the complex anomalous behavior.

Keywords: Quantum Dots; Liquid Droplet Etching; Photoluminescence; Thermally Assisted Tunneling