Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 46: Poster 2
HL 46.65: Poster
Donnerstag, 29. März 2007, 15:00–17:30, Poster A
Resonant photoluminescence up-conversion in a multi quantum well structure mediated by surface acoustic waves — •Stefan Völk1, Jens Ebbecke1, Achim Wixforth1, Dirk Reuter2, and Andreas Wieck2 — 1Institut für Physik der Universität Augsburg, Experimentalphysik I, 86135 Augsburg, Germany — 2Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
We have investigated the excitation emission spectrum of a multi quantum well (MQW) structure under the influence of a surface acoustic wave (SAW). Electron-hole pairs can be excited by laser light in semiconductor structures which form excitons at low temperatures.
The recombination of electron-hole pairs leads to emission of photoluminescence (PL) light. This emission energy is in general equal or smaller than the energy of the optical excitation source. In quantum well (QW) structures the emission energy is defined by the lowest quantized energy levels.
PL up-conversion means that the energy of emitted photons is higher than the excitation energy. Such a process can be observed in MQW structures with QWs of different widths by applying a SAW. We explain this effect through a dynamic conduction and valence band modulation leading to a resonant charge carrrier population of QWs.