Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 64: Quantum Dots and Wires: Optical Properties VI
HL 64.1: Vortrag
Freitag, 26. März 2010, 10:15–10:30, H14
Elastic strain engineering of quantum dot excitonic emission in nanomembranes and optical resonators — •Fei Ding1, Ranber Singh2, Johannes Plumhof1, Tim Zander2, Gabriel Bester2, Armando Rastelli1, and Oliver Schmidt1 — 1Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany — 2Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
We study the effect of an external biaxial stress on the light emission of single InGaAs/GaAs (001) quantum dots (QD) embedded in a 200 nm-thick-membrane. Reversible and bi-directional spectral tuning of QD excitonic emission is demonstrated via a simple electro-mechanical device. The most intriguing finding is that biaxial strain is a reliable tool to engineer the QD electronic structure and reach color coincidence between exciton and biexciton emission, providing a vital prerequisite for the generation of polarization entangled photon pairs through a time reordering strategy. The physical origin of this new phenomenon is discussed based on the empirical pseudopotential calculations.
With similar technique we study the effect of biaxial stress on single QDs embedded in microring resonators. The microrings can be reversibly stretched or squeezed, resulting in a controllable engineering of both QD emissions and optical modes. Our results open up a new tuning strategy to study cQED with semiconductor quantum dots.