Chemistry and structure of BaTiO3 ultra-thin films grown by different O2 plasma power

• DOI: 10.1016/j.cplett.2013.12.030
• Publication Date: 2013-12-20T13:08:04Z
• Authors: J.L. Wang; J. Leroy; G. Niu; G. Saint-Girons; B. Gautier; B. Vilquin; N. Barrett
• Keywords: Plasma Chemistry

We present a study of the chemical and atomic properties of 5 nm TiO2-terminated BaTiO3 (001) epitaxialfilms on Nb-doped SrTiO3, as a function of the atomic oxygen plasma power for film growth. Lowerplasma power produces non-stoichiometric films with oxygen vacancies and Ti3+ ions. The larger Ti3+ion radius and the in-plane clamping gives rise to an increase in the out-of-plane lattice parameter.XPS measures the Ti3+ concentration and the concomitant increase in dissociative water uptake in thefilm, giving rise to on-top OH adsorption on surface Ti, proton adsorption on surface oxygen, and a nearsurface Ba-OH environment.