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HL: Fachverband Halbleiterphysik

HL 9: Quantum Dots: Preparation and Characterization

HL 9.8: Vortrag

Montag, 20. März 2017, 11:45–12:00, POT 112

Quantum Dots grown by Local Droplet Etching on GaAs (111)A Substrates — •Julian Ritzmann¹, Nand Lal Sharma², Dirk Reuter², Carolin Lüders³, 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)[1]. 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[2]. 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.

[1] T. Mano et al., Appl. Phys. Express 3, 065203 (2010).

[2] Ch. Heyn et al., Appl. Phys. Lett. 94, 183113 (2009).