Dresden 2003 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DF: Dielektrische Festkörper

DF 7: Poster

DF 7.14: Poster

Mittwoch, 26. März 2003, 14:30–18:00, P2a

Formation of epitaxial BaTiO₃/SrTiO₃ multilayers grown on Nb-doped SrTiO₃ (001) substrates — •Alina Visinoiu¹, Roland Scholz¹, Soma Chattopadhyay², Marin Alexe¹, Dietrich Hesse¹, and Ulrich Gösele¹ — ¹Max Planck Institute of Microstructure Physics, D-06120 Halle (Saale), Germany. — ²Argonne National Laboratory, Advanced Photon Source, MRCAT-Sector 10, 9700 South Cass Avenue, Argonne, IL 60439, USA.

Epitaxial BaTiO₃/SrTiO₃ multilayers were grown on Nb-doped SrTiO₃ (SrTiO₃:Nb) (001) substrates by pulsed laser deposition. The formation of epitaxial BaTiO₃/SrTiO₃ multilayers was studied in terms of growth mechanism including surface morphologies, crystalline orientations, microstructures, and BaTiO₃/SrTiO₃ interfaces. Epitaxial BaTiO₃ films are growing with a layer-then-island (Stranski-Krastanov) mechanism. X-ray diffraction and cross-sectional high resolution transmission electron microscopy confirm the epitaxy of these films. Up to a thickness of 6 nm the BaTiO₃ films showed no defects. A sharp BaTiO₃/SrTiO₃ interface was observed, while the SrTiO₃/BaTiO₃ interface was rough, probably due to different growth mechanisms of the two materials or due to an asymmetry of the mobility of Ba and Sr atoms reaching the SrTiO₃ and BaTiO₃ layers. This feature is significant in view of actual efforts to grow epitaxial superlattices involving very thin individual layers of BaTiO₃ and/or SrTiO₃. Electrical characterization of BaTiO₃ films and BaTiO₃/SrTiO₃ multilayers was performed in terms of dielectric properties.