Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster I: Devices, Quantum Dots and Quantum Wires
HL 31.41: Poster
Dienstag, 23. März 2010, 18:30–20:30, Poster D1
Control of the charge state of quantum dots and quantum posts by surface acoustic waves — •Florian J. R. Schülein1, F. Knall1, S. Völk1, D. Reuter2, A. D. Wieck2, T. A. Truong3, H. Kim3, J. He3, P. M. Petroff3, A. Wixforth1, and H. J. Krenner1 — 1Lehrstuhl für Experimentalphysik I, Universität Augsburg, Universitätsstr. 1, 86159 Augsburg, Germany — 2Lehrstuhl für Angewandte Festkörperphysik, Universitätsstr. 100, 44780 Bochum, Germany — 3Materials Department, University of California, Santa Barbara, CA 93106, United States
We demonstrate that surface acoustic waves (SAW) can be used to control the carrier capture dynamics into zero-dimensional semiconductor nanostructures. Sharp emission lines from a single self-assembled quantum dot (QD) are identified which change dramatically under the influence of a SAW: We observe the switching between different emission lines as the SAW power is increased. We observe both red and blue spectral shift which allows us to exclude heating effects as the underlying mechanism. In a defined SAW power range, we observe switching between the two emission lines of positively charged and neutral excitons. For QDs, we observed a hysteretic behavior during SAW sweeps attributed to carrier localization and release from shallow traps in the surrounding wetting layer by the SAW. Switching between negatively charged and neutral excitons was also observed for self-assembled quantum posts (QP) which are embedded in a lateral matrix quantum well. These QPs exhibit an even sharper switching behavior without hysteresis at lower SAW power compared to QDs.