Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 51: Poster IV

HL 51.6: Poster

Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D

Calculations of the optical properties of ZnO microcavities for Bose-Einstein condensation — •Chris Sturm, Rüdiger Schmidt-Grund, Jan Sellmann, Helena Hilmer, Bernd Rheinländer, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, 04103 Leipzig

Exciton-polaritons in ZnO based resonators are of interest since they are promising candidates for the realization of Bose-Einstein-Condensation (BEC) at room temperature and above. The exciton-polaritons are quasi-particles which are formed due to the coupling between light and excitons in microcavities embedded between two Bragg mirrors. The properties of the active medium of the microcavitiy determine the temperature at which BEC occurs. Due to its large exciton-binding energy of 60 meV and its large exciton oscillator strength ZnO is a promising material for the realization of BEC at temperature up to 560 K [1].

We calculate the reflectivity and the transmitivity of ZnO based resonators. The dielectric function, which is needed for the calculation, is taken from our ZnO films obtained by ellipsometry. The Rabi-splitting and the mode splitting were calculated. Based on these results the occupation of the exciton-polaritons in the momentum space was calculated and the critical exciton-polariton density and the corresponding excitation energy were estimated. These theoretical investigations were used to design the resonators.

M. Zamfirescu et al., Phys. Rev. B 65, 161205R (2001).