Growth of (Ba,Sr)TiO3 thin films by the hydrothermal-electrochemical method and effect of oxygen evolution on their microstructure

Thin films in the system BaTiO3-SrTiO3 have been grown on Ti electrodes with control of the Ba/Sr composition in aqueous solutions of (Ba, Sr)(OH)(2) by the hydrothermal-electrochemical method. Barium contents of the solid-solution films were always lower than those of the synthesis solutions used. The BaTiO3 and the (Ba, Sr)TiO3 solid-solution films included ''crater-shape'' defects that resulted from the breakaway of the growing film, whereas no such defects were observed in the SrTiO3 film. This dependence of the defect generation on the film composition was interpreted to be caused by differences of anodically evolved oxygen gas pressure in ''short-circuiting paths'' that exists characteristically in the films grown by this method.