Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 51: Poster IV
HL 51.1: Poster
Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D
Redistribution of excitonic photoluminescence transitions mediated by surface acoustic waves — •Stefan Völk1,2, Jens Ebbecke1,2,3, Achim Wixforth1,2, Dirk Reuter4, and Andreas Wieck4 — 1Institut für Physik der Universität Augsburg, Experimentalphysik I, 86159 Augsburg, Germany — 2Center for NanoScience (CeNS), 80539 Munich, Germany — 3School of Engineering and Physical Science, Heriot-Watt University, Edinburgh, EH14 4AS, UK — 4Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
Quantum wells in semiconductor heterostructures can be populated optically by electron-hole pairs which form excitons at low temperatures. Recombination of excitons leads to emission of photoluminescence (PL) light. In earlier experiments there was shown that the PL of a single QW can be quenched by a surface acoustic wave (SAW).
We have investigated the excitation spectrum of a system consisting of different wide GaAs quantum wells. As the transition energies depend on two parameters - quantum well depth and width - the PL spectrum of our multi quantum well (MQW) system shows several peaks.
Surprisingly some of these peaks don't reveal the characteristic quenching when a SAW is applied. In some cases even an amplification of PL intensity can be observed. The explanation of this controversy effect is still under debate. Newer experiments on the MQW system suggest excitonic effects.