Epitaxial BaTiO 3 (100) films on Pt(100): A low-energy electron diffraction, scanning tunneling microscopy, and x-ray photoelectron spectroscopy study

• Published in: The Journal of chemical physics 2011-09, Vol.135 (10), p.104701-104701-6
• Main Authors: Förster, Stefan, Huth, Michael, Schindler, Karl-Michael, Widdra, Wolf
• Format: Article
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.3633703

The growth of epitaxial ultrathin BaTiO 3 films on a Pt(100) substrate has been studied by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and x-ray photoelectron spectroscopy (XPS). The films have been prepared by radio-frequency-assisted magnetron sputter deposition at room temperature and develop a long-range order upon annealing at 900 K in O 2 . By adjusting the Ar and O 2 partial pressures of the sputter gas, the stoichiometry was tuned to match that of a BaTiO 3 (100) single crystal as determined by XPS. STM reveals the growth of continuous BaTiO 3 films with unit cell high islands on top. With LEED already for monolayer thicknesses, the formation of a BaTiO 3 (100)-(1 × 1) structure has been observed. Films of 2-3 unit cell thickness show a brilliant (1 × 1) LEED pattern for which an extended set of LEED I-V data has been acquired. At temperatures above 1050 K the BaTiO 3 thin film starts to decay by formation of vacancy islands. In addition (4 × 4) and (3 × 3) surface reconstructions develop upon prolonged heating.