Hydrothermal epitaxy of BiFeO3 films on SrTiO3 substrates

Epitaxial multiferroic BiFeO3 thin films were grown on SrTiO3 substrates by the hydrothermal method at 200 °C in aqueous solutions of 6–12 M KOH. Films grown at 9 M were the most coalesced with a dense and island-like morphology. It was also the most well aligned film with a full width at half maximum of 0.436. Irrespective of whether the substrates for the 9 M KOH condition were in the face-up and face-down configuration, all films grew epitaxially in the [100] directions. However, films grown in the face-up configuration contained BiFeO3 nanoparticles on the film surfaces.