Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster II
HL 31.37: Poster
Dienstag, 26. Februar 2008, 16:30–19:00, Poster D
Polarisation properties of single lateral InGaAs quantum dot molecule photoluminescence — •Marcus Witzany1, Claus Hermannstädter1, Gareth Beirne1, Lijuan Wang2, Armando Rastelli3, Oliver Schmidt3, and Peter Michler1 — 1Institut für Halbleiteroptik und Funktionelle Grenzflächen, Universität Stuttgart, Allmandring 3, 70569 Stuttgart — 2Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart — 3Institut für Integrative Nanowissenschaften, IFW Dresden, Helmholtzstr. 20, 01069 Dresden
The photoluminescence of single lateral InGaAs quantum dot molecules (QDM) grown by a unique combination of molecular beam epitaxy and in-situ etching has been investigated with respect to polarisation. The molecules are composed of two quantum dots that are coupled along the [1-10] crystal direction via electron tunneling. An electric field along the coupling axis can be applied in a lateral geometry by depositing lithographically processed gold electrodes on the sample surface. An anomalous Stark shift and a change in relative intensities of the excitonic emission lines may be obtained by applying an electric field parallel to the molecule axis. This has been shown to indicate that the coupling mechanism (electron tunneling) can be controllably manipulated [Phys. Rev. Lett. 96, 137401]. We have performed linear polarisation dependant PL measurements on single molecules under the influence of different field strengths and directions. The degree of linear polarisation observed substantiates that the electronic wavefunction is elongated along the molecule axis.