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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.126: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Polaritonic effects in wide-gap semiconductors as a function of temperature — •Marie-Elena Kleemann1, Sviatoslav Shokhovets1, Gerhard Gobsch1, and Oliver Ambacher2 — 1Technische Universität Ilmenau, Ilmenau, Deutschland — 2Frauenhofer-Institut für Angewandte Festkörperphysik, Freiburg, Deutschland
Polaritonic effects are regarded as the properties of an excitonic crystal with the spatial dispersion, which is related to the ability of the exciton to move through the lattice.The influence of an increasing temperature on the excitonic polaritons consists in the increasing damping (broadening of optical transitions). In the limiting case of a high damping, the polaritonic effects should become not observable.
In this work we measured polarized reflectance and photoreflectance for high-quality c-plane epitaxial films of wurzite GaN and ZnO as well as of a-and m-plane ZnO crystals in the range from liquid-helium temperatures up to room temperature. In order to reveal the presence of polaritonic effects and their temperature dependence, the data is analyzed using two different models of the dielectric function, which describe the experimental results. While in the first model spatial dispersion is implemented, it is disregarded in the second model.