Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 94: Poster IV A (Laser; Devices; Heterostructures; Surfaces, interfaces and defects)
HL 94.10: Poster
Donnerstag, 19. März 2015, 14:00–20:00, Poster B
Local Droplet Etching on GaAs (111)A substrates — •Julian Ritzmann1, Rüdiger Schott1, Nandlal Sharma2, Dirk Reuter1,2, Arne Ludwig1, and Andreas D. Wieck1 — 1Ruhr-Universität Bochum, Universitätstraße 150, D-44780 — 2Universität Paderborn, Warburger Straße 100, D-33098
The generation of entangled photon pairs is a key to practical quantum communications. In the case of biexcitons in Stranski-Krastanov-grown quantum dots, the fine structure splitting (FSS) of the energy levels causes the transition paths of biexciton and exciton transitions 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 quantum dots exhibit a strong distribution in size, resulting in rather broad photoluminescence 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 first results for different parameters on the LDE and LDE QD process on GaAs (111)A surfaces using atomic force microscopy and photoluminescence measurements.
[1] T. Mano et al., Appl. Phys. Express 3, 065203 (2010).
[2] Ch. Heyn et al., Appl. Phys. Lett. 94, 183113 (2009).