Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 61: Poster II: Materials, Interfaces and Heterostructures

HL 61.33: Poster

Donnerstag, 25. März 2010, 18:00–20:00, Poster D1

Polarization behaviour of the exciton-polariton emission — •Chris Sturm, Helena Hilmer, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, 04103 Leipzig

The formation and properties of exciton-polaritons in microresonators have been intensively investigated in the last years, since they can undergo a Bose-Einstein condensation (BEC). In this work we present the polarization behaviour of the exciton-polariton emission of a ZnO based resonator and deduce information on the relaxation into the ground state, such as the scattering rates. The resonator was grown by pulsed laser deposition consisting of a wedge shape cavity in order to investigate the exciton-polariton properties at different detunings. The photoluminescence (PL) spectra show a strong polarization dependence of the emission of the lower polariton branch (LPB). A maximum energy splitting of about 5 meV between s- and p-polarized light is obtained for an emission angle of about 34 ^∘, caused by the uncoupled cavity-photon mode. The occupation (connected with PL-intensity) of the LPB for the two different polarizations was analyzed and we found a larger bottleneck effect for the p- than for the s-polarized light. With increasing detuning the magnitude of the bottleneck effect decreases and also the splitting between the two polarizations, i.e. the relaxation into the ground state is enhanced. Therefore large positive detunings are preferred for ZnO based resonators in order to reach a BEC, which is in agreement with theory [1].

1. R. Johne et al., Appl. Phys. Lett. 93, 249902 (2008).