Microstructural development of BaTiO₃ heteroepitaxial thin films by hydrothermal synthesis

The hydrothermal growth of epitaxial BaTiO₃ thin films on single-crystal SrTiO₃ substrates occurs by the island growth mode. The aqueous solution chemistry is found to control interfacial characteristics and plays an important role in controlling film formation and faceting. Island faceting can be changed by the introduction of additional cations during synthesis. Electrophoretic data, confirmed by adsorption measurements, show that barium is a potential determining counterion and adsorbs on SrTiO₃ surfaces. Initial electrical measurements show that the BaTiO₃ films have a dielectric constant of 141 with a loss tangent of 0.9 that decreases with heat treatment.