Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 14: Heterostructures
HL 14.5: Talk
Monday, February 25, 2008, 10:30–10:45, ER 164
PLD growth of ZnO resonators based on all-oxide Bragg reflectors — •Helena Hilmer, Jan Sellmann, Chris Sturm, Rüdiger Schmidt-Grund, Holger Hochmuth, Jesús Zúñiga Pérez, Gregor Zimmermann, Jörg Lenzner, Christian Czekalla, Gabriele Benndorf, Michael Lorenz, Bernd Rheinländer, Anatoli Serghei, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig
High quality microcavities are crucial for reaching strong coupling of excitons and photons (exciton-polaritons) and finally to obtain a Bose-Einstein condensate of exciton-polaritons. For this, high reflective mirrors and a cavity with smooth interfaces are necessary. Furthermore, the active medium should be distinguished by a narrow linewidth of the optical emission. For this purpose, ZnO-based microcavity resonators are promising systems.
Planar resonators with ZnO as cavity material and active medium embedded between ZrO2/Al2O3 Bragg reflectors have been grown on c-plane sapphire substrates by means of pulsed laser deposition. For the Bragg reflectors reflectivity values up to 99.8% at 3.3 eV and smooth interfaces (Ra=0.5 nm) have been achieved. The structural and optical quality, i.e. smooth interfaces and narrow exciton linewidth, of the ZnO-layer are still a challenge. We discuss the influence of deposition rates, formation of a thin nucleation layer as well as replacing ZrO2 by YSZ on the properties of the cavity. The optical properties were analysed by spectroscopic ellipsometry and photoluminescence. The structural properties were examined by means of AFM and XRD.