Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Quantum dots: Preparation and characterization

HL 44.9: Vortrag

Mittwoch, 18. März 2015, 11:45–12:00, EW 203

Growth of Site-Controlled InAs Quantum Dots by MOVPE — •Marc Sartison, Matthias Paul, Jan Kettler, Michael Jetter, and Peter Michler — Universität Stuttgart, Institut für Halbleiteroptik und Funktionelle Grenzflächen and Research Center SCoPE, Allmandring 3, 70569 Stuttgart

In the last decade, it has been demonstrated, that semiconductor quantum dots (QDs) have the potential to be excellent light sources for the application in single-photon devices. Normally, QDs with a high optical quality and structrual purity are grown self-assembled with a low spatial density. Hence, it is a challenging task to integrate QDs into optical circuits on chip, a precise control of the QD position is essential. It also has been shown, that the surface potential can be locally modified to create sites of higher nucleation probability by prepatterning the substrates. In this contribution, we present approaches of the site-controlled growth of InAs QDs on prepatterned GaAs substrates. To create nucleation sites, the substrate is structured with a hexagonal hole pattern, which is etched either by wet, or a combination of wet and dry chemical etching. Afterwards, the templates are overgrown with different GaAs buffer structures in our MOVPE system. The evolution of the holes and the nucleation behavior of the InAs QDs is monitored by AFM and SEM measurements. To reveal the optical characteristics, the QDs were capped with a GaAs layer. The micro-photoluminescence measurements show single QD emission lines and two wetting layer peaks resulting from variations in the wetting layer thickness inside the holes and in the planar region in between.