Dresden 2009 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 15: Thin Films and Nanostructures II

DF 15.2: Vortrag

Donnerstag, 26. März 2009, 11:00–11:20, WIL B321

Characterization of PbSc_0.5Ta_0.5O₃ epitaxial thin films prepared by Pulsed Laser Deposition — •Anuj Chopra, Marin Alexe, Balaji Ishwarrao Birajdar, Ionela Vrejoiu, and Dietrich Hesse — Max Planck Institute of Microstructure Physics, Halle, D-06120, Germany

Epitaxial PbSc_0.5Ta_0.5O₃ (100) (PST) thin films of thickness 70 nm were deposited on vicinal SrTiO₃ (STO) (100) substrates with a layer of SrRuO₃ (SRO) as a bottom electrode by pulsed laser deposition (PLD) at 823K. Their crystal orientation, topography and microstructure were analysed by X-ray diffraction, atomic force microscopy (AFM) and transmission electron microscopy (TEM), respectively. The films deposited at temperature higher than 823K showed the presence of pyrochlore phase whereas films grown at 823K were perovskites. The in-plane and out-of-plane epitaxial relationships were studied by Φ and θ-2θ scans respectively. AFM revealed a smooth surface with RMS of 1.1nm. Superstructure reflections obtained in the TEM diffraction patterns of the films confirm cation ordering. The films were characterized by using polarization vs electric field (P-E) and switching current vs voltage (I-V) measurements. Polarization of the epitaxial films at zero electric field was 2µC/cm² at room temperature. Cation ordering with post annealing of the films is still under investigation. This work describes the preparation and characterization of epitaxial films of PST (100) for the first time and indicates PST as a potential candidate for infra-red image sensor applications.