Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 74: Quantum dots: Optical properties
HL 74.8: Vortrag
Donnerstag, 14. März 2013, 11:30–11:45, H16
Optical excitation channels of a single site-controlled quantum dot — •Ole Hitzemann1, Erik Stock1, André Strittmatter1, Andrei Schliwa1, Jan-Hindrik Schulze1, Tim D. Germann1, David Quandt1, Waldemar Unrau1, Udo W. Pohl1, Axel Hoffmann1, Dieter Bimberg1, and Vladimir Haisler2 — 1Institut für Festkörperphysik, Technische Universität Berlin, Germany — 2Institute of Semiconductor Physics, Russian Academy of Sciences, Novosibirsk, Russian Federation
Direct and phonon-mediated channels of optical excitation are studied on a single isolated site-controlled InGaAs/GaAs quantum dot (QD). The nucleation site was precisely defined by a distant buried stressor formed by controlled partial oxidation of a sandwiched AlGaAs layer as part of a mesa structure.
Above a sub-micrometer aperture we observe sharp luminescences lines, originating from a single QD as demonstrated by autocorrelation measurements. Micro photoluminescence excitation spectroscopy shows efficient excitation channels through hybridization with the wetting layer, excited states, and coupling with phonon modes as well as distinctively different photoluminescence spectra for different excitation energies. Excitation power dependent measurements reveal the saturation behavior of excitonic and high excitation luminescence lines.