Growth Morphology and Crystal Orientation of KNbO3 Film on SrTiO3 by Liquid Phase Epitaxy

Single-crystalline KNbO3 (001) films were successfully formed on the SrTiO3 (001) substrate from high temperature K2CO3–Nb2O5 solution by liquid phase epitaxy (LPE) technique. The growth morphology was strongly influenced by the melt composition and film growth temperature. Translucency and defect formation were observed in the KNbO3 films grown from the melt with K2CO3 content of 52.5 mol% which is utilized for the bulk crystal growth. In contrast, a transparent single-phase epitaxial film was obtained by lowering the growth temperature from 1051 to 900°C using the melt with high K2CO3 content of 65.0 mol%. The crystallographic relationship between KNbO3 film and SrTiO3 substrate was also investigated by the precession X-ray photography.