Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 89: Optical Properties II
HL 89.7: Vortrag
Freitag, 18. März 2011, 12:00–12:15, POT 251
Surface acoustic wave induced electron tunneling from an InGaAs/GaAs wetting layer — •Jens Pustiowski1, Florian J.R. Schülein1, Dirk Reuter2, Andreas D. Wieck2, Max Bichler3, Kai Müller3, John J. Finley3, Achim Wixforth1, and Hubert J. Krenner1 — 1Lehrstuhl für Experimentalphysik I, Universität Augsburg, 86159 Augsburg, Germany — 2Lehrstuhl für Angewandte Festkörperphysik, 44780 Bochum, Germany — 3Walter-Schottky-Institut, 85748 Garching, Germany
We report on a stroboscopic technique to probe the dynamic modulation controlled by a surface acoustic wave (SAW) of the photoluminescence (PL) of a wetting layer which is formed during the growth of InGaAs/GaAs quantum dots. A short laser pulse (τ < 100ps) is actively phase locked to the frequency of the SAW and the relative phase between laser excitation and SAW can be precisely controlled [1]. Thus, we are able to map one complete cycle of the SAW and study the PL quenching and its modulation in the time domain. For low SAW powers the observed modulation with the fundamental period of the SAW arises from different mobilities of electrons and holes. This imbalance leads to different ionization efficiencies in the type-II band gap modulation induced by the SAW. At high SAW power levels, the modulation period doubles which can be readily explained by SAW induced tunneling induced by the vertical piezoelectric field component.
[1] S. Völk et al., arxiv:1011.1898 (2010).