Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session: Quantum Dots and Wires - Transport & Optical Properties

HL 44.20: Poster

Dienstag, 27. März 2012, 09:30–12:30, Poster D

Micro-magneto-optics and photocurrent-spectroscopy of large In_0.3Ga_0.7As quantum dots — •Peter Gold¹, Manuel Gschrey¹, Andreas Löffler¹, Sven Höfling¹, Alfred Forchel¹, Martin Kamp¹, and Stephan Reitzenstein^1,2 — ¹Universität Würzburg, Technische Physik, Am Hubland, D 97074 Würzburg — ²Present address: Institute of Solid State Physics, Hardenbergstrasse 36, Technische Universität Berlin, D-10623 Berlin

Quantum dot (QD) microcavities are of high interest for the observation of cavity quantum electrodynamics (cQED) effects in the weak or strong coupling regime and their application in quantum light sources. An important parameter that influences the strength of the coupling between light and matter is the oscillator strength f of the involved QD exciton. In this context, laterally elongated In_0.3Ga_0.7As QDs are of particular interest due to their large oscillator strength in the range of f ≈ 40−50. Here we present a comprehensive spectroscopic study on the optical properties of In_0.3Ga_0.7As QDs by applying high resolution micro-magneto-optical and micro-photocurrent (µPC) spectroscopy. These experimental results are compared to those obtained from standard In_xGa_1-xAs QDs with an indium content of x=0.6 and x=1.0, respectively, and oscillator strengths of f≈10. We observe particular large diamagnetic coefficients for the In_0.3Ga_0.7As QDs and a clear correlation between the diamagnetic coefficient and the Landé g-factor of the QDs. In addition, a strong fano-like asymmetry of the X lineshape is observed in µPC. The experimental results are in good agreement with numerical simulations.