Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 74: Quantum dots: Optical properties

HL 74.8: Talk

Thursday, March 14, 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.