Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 32: Poster I: Group II - Oxides

HL 32.25: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D1

The refractive index of zinc oxide microwire single crystals — Christian Czekalla, Philipp Kühne, Chris Sturm, •Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Linnéstr. 5, 04103, Leipzig, Germany

Among a large number of applications, zinc oxide (ZnO) single crystals (bulk and micro- and nanowires) are expected to form important building blocks for future optoelectronic devices like light emitting and laser diodes. Optical resonances from ZnO structures have been observed by a number of groups in the past years.

In most of the publications, modeling of the mode structure, especially in the near bandgap spectral region, is difficult because the energy dependent refractive index n(E) is typically not known. Additionally, in case of the self assembled micro- and nanowires, the structures are too small to perform spectroscopic ellipsometry to determine n(E).

We compare n(E) obtained from (a) spectroscopic ellipsometry measurements of ZnO bulk single crystals and (b) spatially resolved photoluminescence measurements of ZnO microwires employing a plane wave whispering gallery mode model for the observed resonances. We discuss the differences between the results obtained from the two methods and their mutual impact, leading to a highly precise determination of n(E) in an energy range between 1.80 eV and 3.25 eV and for temperatures between 10 K and 295 K.