Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 77: Quantum Dots and Wires: Optical Properties II (mainly Luminescence and Electronic Structure)
HL 77.1: Talk
Thursday, March 29, 2012, 09:30–09:45, EW 203
Optical properties of Arsenide-based nanowire heterostructures — •Lucas Schweickert1, Daniel Rudolph1, Watcharapong Paosangthong1, Dance Spirkoska1, Max Bichler1, Gerhard Abstreiter1,2, Gregor Koblmüller1, and Jonathan J. Finley1 — 1Walter Schottky Institut, TU München, Garching, Germany — 2TUM Institute for Advanced Study, Garching, Germany
We report the investigation of the optical properties of single AlGaAs/GaAs core/shell nanowires using low temperature micro-photoluminescence (PL) spectroscopy. The nanowires are grown using a catalyst free method using molecular beam epitaxy on lithographically patterned SiO2-Si(111) substrates [1]. Capping the GaAs nanowires with a thin AlGaAs shell is found to result in a drastic >103 enhancement of the PL intensity. The influence of the capping shell thickness on the PL intensity was investigated for shell thicknesses in the range 8-100nm, under conditions where free carriers are photo-generated in the entire structure and solely in the GaAs core. Time-resolved and temperature-dependent PL studies were performed to obtain a better understanding of the mechanisms that limit the internal quantum efficiency. Furthermore, we will present first results obtained on GaAs-AlGaAs axial nanowires with axial In-containing segments. It is envisaged that optically active quantum dots can be controllably incorporated into axial core-shell nanostructures.
[1] D. Rudolph et al., Nano Lett. 11, 3848 (2011)