Regensburg 2010 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 3: Poster I: Nano- and microstructured dielectrics, surfaces and interfaces, dielectric composites

DF 3.7: Poster

Montag, 22. März 2010, 15:00–17:30, Poster D1

Investigation of the optical phonon modes of BaTiO₃ thin films using Raman scattering spectroscopy and IR spectroscopic ellipsometry — •Christian Kranert, Chris Sturm, Stefan Schöche, Rüdiger Schmidt-Grund, Holger Hochmuth, and Marius Grundmann — Universität Leipzig, Semiconductor Physics Group, Institut für Experimentelle Physik II, Leipzig, Germany

The coupling of the switchable and non-switchable polarization of ferroelectric and pyroelectric materials in heterostructures results in new physical effects which can be used for modulators, sensors and, memories.[1] The properties of the ferroelectric polarization are strongly related to the phonon spectrum. In this work we present the investigation of the optical phonon modes of ZnO and BaTiO₃ and ZnO-BaTiO₃ heterostructures by Raman spectroscopy and infrared spectroscopic ellipsometry. A comparison of the phonon modes in heterostructures with those of single films provides access to the properties of the polarization interaction in these heterostructures.

The BaTiO₃ and ZnO thin films as well as the BaTiO₃-ZnO heterostructures were grown by pulsed laser deposition (PLD). The Raman measurements were carried out using two different lasers at a wavelength of 532 nm and 325 nm, respectively, in order to realize an excitation below as well as above the band gap of both the materials which allows to control the penetration depth of the probe-light in the films and heterostructures, respectively.

[1] O. Auciello and R. Ramesh, MRS Bull. Vol. 29, No. 7 (1996)