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DS: Dünne Schichten

DS 24: Poster presentation

DS 24.35: Poster

Dienstag, 28. März 2006, 15:00–17:30, P2

Modeling asymetric polarization hysteresis of BaTiO₃-ZnO heterostructures — •V. M. Voora¹, N. Ashkenov¹, T. Hofmann², M. Lorenz¹, M. Grundmann¹, and M Schubert² — ¹Institut für Experimentelle Physik II, Universität Leipzig, Leipzig, Germany — ²CMRA, University of Nebraska-Lincoln, Lincoln, USA

The spontaneous polarizations of appropriately oriented wurtzite and perovskite material layers cause bound charges at their interfaces. Whereas the wurtzite-type polarization is inherently tied to one distinct lattice direction, the spontaneous polarization can be reversed within the perovskite lattice upon application of external electric fields. We have successfully grown high-quality Pt-BaTiO₃-ZnO-Pt layer structures by Pulsed Laser Deposition on Si-substrate and investigated the structural, electrical, and optical properties of these structures. The asymetric polarization hysteresis of the Si-Pt-BaTiO₃-ZnO-Pt heterostructures show distinct fingerprints of a Schottky-type junction formed at the BaTiO₃/ZnO interface. For positive voltage direction the hysteresis is dominated by a clear reverse diode behavior, whereas for the negative voltage direction the clear switching behavior of BaTiO₃ is present. A quantitative model analysis of the electrical measurements is presented.