Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.84: Poster
Thursday, March 17, 2011, 18:00–21:00, P4
Voltage-dependent excited state spectroscopy of single lateral InGaAs quantum dot molecules — •Meike Seible1, Matthias Heldmaier1, Jie Peng2, Gabriel Bester2, Lijuan Wang2, Armando Rastelli3, Oliver G. Schmidt3, and Peter Michler1 — 1Institut für Halbleiteroptik und Funktionelle Grenzflächen, Allmandring 3, 70569 Stuttgart, Germany — 2Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany — 3Institut für Integrative Nanowissenschaften IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
We investigate single laterally coupled quantum dot molecules (QDMs) which are grown using a combination of molecular beam epitaxy and in situ atomic-layer precise etching. Each QDM consists of two individual quantum dots (QDs) which are coupled along the [1-10] crystal direction via electron tunneling, while the holes are strongly localized in either of the QDs. The electronic coupling can be influenced by applying an electric field along the molecular coupling axis. This leads to a shift between the intensities of the excitonic emission lines of the respective dots. For the investigation of the behaviour of the excited states in this system under different coupling conditions, detailed photoluminescence excitation (PLE) spectroscopy measurements have been carried out, using a wideband tunable Ti:Sapphire laser source under systematic variation of the applied lateral electric field. We compare these results with theoretical calculations of absorption spectra, using an empirical many-body pseudo-potential approach with random composition of the QDMs.