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.