Hydrothermal Growth and Orientation of LaFeO Epitaxial Films.

LaFeO thin films were successfully epitaxially grown on single-crystalline SrTiO substrates by the one-step hydrothermal method at a temperature of 320 °C in a 10 mol/L KOH aqueous solution using La(NO) and Fe(NO) as the raw materials. The growth of the films was consistent with the island growth mode. Scanning electronic microscopy, elemental mapping, and atomic force microscopy demonstrate that the LaFeO thin films cover the SrTiO substrate thoroughly. The film subjected to hydrothermal treatment for 4 h exhibits a relatively smooth surface, with an average surface roughness of 10.1 nm. X-ray diffraction in conventional Bragg-Brentano mode shows that the LaFeO thin films show the same out-of-plane orientation as that of the substrate (i.e., (001)||(001)). The in-plane orientation of the films was analyzed by φ-scanning, revealing that the orientational relationship is [001]||[001]. The ω-rocking curve indicates that the prepared LaFeO films are of high quality with no significant mosaic defects.