Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 19: Silicon and Germanium
HL 19.5: Talk
Monday, March 14, 2011, 15:30–15:45, POT 251
Enhanced luminescence of self-assembled germanium islands in silicon photonic crystal nanocavities — •Stefan Lichtmannecker1, Norman Hauke1, Thomas Zabel1, Fabrice Laussy1, Dominique Bougeard2, Gerhard Abstreiter1, Yasuhiko Arakawa3, and Jonathan Finley1 — 1Walter Schottky Institut, Garching — 2Universität Regensburg — 3University of Tokyo, Japan
We present optical investigations of two dimensional silicon photonic crystal defect nanocavities with high density (109 cm−2) germanium islands acting as an internal light source. Power and time dependent micro photoluminescence (µ–PL) spectroscopy at a lattice temperature of 25K reveals an enhancement of the photoluminescence signal recorded from the cavity modes by a factor of 350x compared to the unprocessed regions of the device. This enhancement is not fully accounted for spatial redistribution of the emission profile through the cavity mode. Quantitative analysis of power dependent µ–PL measurements and comparison with time resolved measurements suggest that the observed enhancement of the cavity mode emission is due to an enhanced internal quantum efficiency via the Purcell effect.
By systematically investigating the dependence of the emission intensity on the cavity Q-factor we observe a clear trend that lower Q-cavities produce the most intense emission. These observations are supported by simulations of our system using a dissipative master equation approach. Supported financially by the DFG via NIM, TUM IGSSE and TUM IAS.