Dresden 2011 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 12: Poster

DF 12.1: Poster

Mittwoch, 16. März 2011, 15:00–17:30, P1

Strontium titanate/barium titanate heterostructures grown by pulsed-laser deposition — •Jan Zippel, Tammo Böntgen, Michael Lorenz, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Institut für Experimentalphysik II, Linnéstraße 5, 04103 Leipzig

Recently, ferroelectric thin films such as BaTiO₃ (BTO) and SrTiO₃ (STO) have been attracted considerable attention due to their properties like ferroelectricity and piezoelectricity being suitable for applications in memories and sensors [1]. Differences in the electronic structure in combination with nearly no optical interface between STO and BTO and the probability to tune the optical properties for superlattices formed by STO and BTO is of interest for optical applications.

Here, we present the optimized growth of BTO and STO on STO (100) substrates using pulsed-laser deposition (PLD) with an in-situ reflection high energy electron diffraction (RHEED) system. The oxygen partial pressure (p(O₂)), the substrate temperature (T_sub) as well as the repetition rate of the laser and the energy density were varied in order to optimize both, the surface quality, controlled by atomic force microscopy (AFM) and the crystalline properties, checked by X-ray diffraction (XRD). The optical properties measured by spectral ellipsometry hardly depend on the crystalline structure. We were able to tune the index of refraction to a point, where optically nearly no difference between STO and BTO is observable at certain wavelength.

[1] James F. Scott, Carlos A. Paz de Araujo, Science (1989), 246, 1400-1405.