Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Poster Session II
HL 24.12: Poster
Dienstag, 13. März 2018, 18:30–20:30, Poster F
Quantum Dots grown by Local Droplet Etching on GaAs (111)A Substrates — •Julian Ritzmann1, Nandlal Sharma2, Dirk Reuter1,2, Henning Moldenhauer3, Jörg Debus3, Arne Ludwig1, and Andreas D. Wieck1 — 1Ruhr-Universität Bochum, D-44780 Bochum — 2Universität Paderborn, D-33098 Paderborn — 3Technische Universität Dortmund, D-44227 Dortmund
The generation of entangled photon pairs is a key to practical quantum communications. In the case of biexcitons in SK-grown quantum dots (QD), the fine structure splitting (FSS) of the energy levels causes the transition paths of biexciton and exciton to be distinguishable. Therefore, we need quantum dots with strongly reduced FSS. This was theoretically proposed and experimentally shown for GaAs quantum dots on (111)A-oriented AlGaAs by droplet epitaxy (DE). However, these QDs exhibit a strong distribution in size resulting in rather broad photoluminescence (PL) spectra. Nearly uniform quantum dots were achieved by filling up nanoholes on (001)-oriented Al(Ga)As with GaAs achieving a PL linewidth of less than 10 meV. These nanoholes were generated via local droplet etching (LDE) of gallium droplets on an Al(Ga)As surface. Our approach is to use LDE for the growth of uniform, triangular QDs on (111)A-oriented substrates with low density and reduced FSS. Here, we present a study on different parameters for the LDE and LDE QD process on GaAs (111)A surfaces using atomic force microscopy, PL and micro-PL.