Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 89: Optical Properties II

HL 89.5: Talk

Friday, March 18, 2011, 11:15–11:30, POT 251

Refractive Index matching of BaTiO₃/SrTiO₃ Heterostructures — •Tammo Böntgen, Jan Zippel, Rüdiger Schmidt-Grund, Michael Lorenz, and Marius Grundmann — Universtät Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5

By altering the growth parameters for BaTiO₃/SrTiO₃ heterostructures we achieved matching of the refractive index for selected wavelengths. Using spectroscopic ellipsometry we have determined the optical properties of these heterostructures and their constituting layers. By systematically varying the growth parameters, the refractive index of the STO layer was tuned such that it crosses the refractive index of BTO. The index matching leads to a vanishing reflectivity at the crossing wavelength. The crossing wavelength varies with the choice of the growth parameters. X-Ray diffraction measurements were carried out on the heterostructures to probe the effect of the growth conditions on the STO lattice parameters. A dependence of the lattice constant on the growth parameters was found, linking the change in the optical properties to the lattice deformation. This kind of index matching can in principal also be achieved for other perovskite ATiO₃ hetero- or multilayer structures. This work was supported by Deutsche Forschungsgemeinschaft in the framework of Sonderforschungsbereich 762 "Functionality of Oxidic Interfaces".