Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 64: Quantum Dots and Wires: Optical Properties VI

HL 64.2: Talk

Friday, March 26, 2010, 10:30–10:45, H14

Effect of substrate thickness on uniaxial strain–induced single quantum dot emission energy tuning — •Klaus D. Jöns¹, Robert Hafenbrak¹, Sven M. Ulrich¹, Lijuan Wang², Fei Ding², Johannes D. Plumhof², Armando Rastelli², Oliver G. Schmidt², and Peter Michler¹ — ¹Institut für Halbleiteroptik und Funktionelle Grenzflächen, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany — ²Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany

The ability to tailor the optical properties of epitaxially grown quantum dots (QDs) is one of the huge advantages of these kind of solid state quantum emitters. In particular, the possibility to tune the emission energy is an important prerequisite to generate indistinguishable photons from two different quantum emitters. In our work we present in–situ emission energy tuning of self–assembled InGaAs/GaAs QDs by uniaxial strain. For this purpose we glued the sample tightly on a piezo stack. Our technique allows to apply tunable tensile and compressive uniaxial strain along the [110] crystal axis perpendicular to the growth direction. The applied strain changes the emission energy of the QD by enlarging respectively reducing the lattice constant and thus the band gap. Micro–photoluminescence measurements at T = 10 K show that the spectral emission of the QDs can be reversibly shifted in a controlled way. We use different substrate thinning techniques to increase the uniaxial strain at the lattice plane of the QDs. This leads to an increased tuning range of the emission energy. Samples with completely removed substrate show an emission tuning range up to 2.8 meV.