Low temperature/low pressure hydrothermal synthesis of barium titanate: Powder and heteroepitaxial thin films

Barium titanate powder and heteroepitaxial thin films were successfully produced by hydrothermal routes at ambient pressure and temperatures less than 100 °C. This processing method provides a simple low temperature route for producing epitaxied barium titanate thin films on single-crystal SrTiO₃ substrates and powders which could also be extended to other systems. A dissolution/reprecipitation growth mechanism also was proposed for the formation of barium titanate by this route using previously published aqueous stability diagrams. Repeated hydrothermal treatments improved film thickness and surface coverage at the expense of increased surface roughness.