Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 94: Quantum wires and nanocrystals: Optical properties
HL 94.5: Talk
Friday, March 15, 2013, 10:30–10:45, H13
Acousto-electric control of exciton dynamics in GaAs/AlGaAs core-shell nanowires containing a single radial GaAs quantum well — •Matthias Weiß1, Jörg Kinzel1, Daniel Rudolph2, Max Bichler2, Gregor Koblmüller2, Gerhard Abstreiter2, Jonathan Finley2, Achim Wixforth1, and Hubert Krenner1 — 1Lehrstuhl für Experimentalphysik 1 / Universität Augsburg, 86159 Augsburg,Germany — 2Walter Schottky Institut / TU München, 85748 Garching, Germany
Radio frequency (RF) surface acoustic waves (SAW) represent a versatile tool to control and manipulate charge and spin excitations in semiconductor quantum structures. Here, we analyze the influence of the dynamic electric field induced by a SAW on the optical emission of single semiconductor nanowires. The investigated NWs consist of a GaAs core and an AlGaAs shell containing a single 5nm wide radial GaAs quantum well (QW). The optical emission is studied by conventional, low-temperature micro-photoluminescence (µ-PL) spectroscopy in combination with a stroboscopic excitation. For both, the GaAs core and the radial QW, at high SAW power, we observe clear signatures of acousto-electric exciton dissociation and conveyance of electrons and holes. However, in an intermediate range of SAW amplitudes, we observe fingerprints of quantum dot (QD)-like emission centers within the narrow QW. These QD manifest themselves by several sharp spectral lines which exhibit dynamic spectral shifts. Moreover, we observe intensity oscillations being connected to the local acoustic phase, which was previously observed by embedded, planar QD structures.