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HL: Fachverband Halbleiterphysik
HL 12: Quantum Dots and Wires: Arsenides
HL 12.5: Talk
Monday, March 14, 2011, 13:00–13:15, POT 151
Strain-tuning of the excitonic fine structure splitting in semiconductor quantum dots — •Johannes D. Plumhof1, Vlastimil Krapek2, Fei Ding1, Klaus D. Jöns3, Robert Hafenbrak3, Petr Klenovsky2, Andreas Herklotz1, Kathrin Dörr1, Armando Rastelli1, Peter Michler3, and Oliver G. Schmidt1 — 1IFW Dresden, Helmholtzstr. 20, D-01069 Dresden — 2Institute of Condensed Matter Physics, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic — 3Institut für Halbleiteroptik und Funktionelle Grenzflächen, University of Stuttgart, Allmandring 3, 70569 Stuttgart
For the creation of polarization entangled photon pairs from semiconductor quantum dots (QDs) it is important to decrease the fine structure splitting (FSS) of the neutral exciton to energies comparable to the emission linewidth. We employ a piezoelectric actuator (PMN-PT) to manipulate the excitonic emission of GaAs/AlGaAs as well as InGaAs/GaAs QDs embedded in ≈200 nm thick (Al)GaAs membranes. By attaching the membranes on the PMN-PT we can apply anisotropic strain to the nanostructures. Polarization resolved µ-photoluminescence spectroscopy is used to estimate the excitonic FSS as well as the orientation of the linear polarization of the emitted light. The strain makes it possible to manipulate the FSS in a range of 70 µ eV. We also observe rotations of up to 70∘ of the linear polarization of the light emitted by neutral excitons. These effects can be explained as an strain-induced anticrossing of the bright excitonic states.