Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 29: Quantum dots: Optical properties II

HL 29.6: Talk

Wednesday, March 25, 2009, 11:00–11:15, BEY 154

Time-resolved µ-photoluminesence investigations of group-III-nitride quantum dots — •Thomas Switaiski, Stefan Werner, Erik Stock, Momme Winkelnkemper, Axel Hoffmann, and Dieter Bimberg — Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin

Small fluctuations in size, shape and composition of self-organized quantum dots (QDs) strongly effect the decay times of localized excitonic transitions. Here, we present time and spatially resolved photoluminesence measurements of single InGaN/GaN QDs. The sample is excited with the second harmonic of a modelocked and tuneable Ti:Sapphire laser through a metallic shadow mask, which improves the lateral resolution and allowing spectroscopy of single QDs. Using eight-band k· p modelling, we show that the built-in piezo- and pyroelectric fields within the QDs cause a sensitive dependence of the radiative lifetimes of the exact QD geometry and composition. Moreover, the radiative lifetimes also depend strongly on the composition of the direct surrounding of the QDs.