Synthesis of KNbO₃ thin film by liquid phase epitaxy method

Abstract

KNbO₃ is one of the most promising lead-free piezoelectric material for substitution of PZT family. In this study, single-crystalline KNbO₃ thin films were gorwn on single-crystalline SrTiO₃(100) substrate by LPE method. The surface morphology depended on the film growth temperature. A lot of defects due to melt-substrate reaction were observed on the film surface in the case for the melt composition of K/Nb=52.5/47.5. In contrast, the film surface obtained at a lower growth temperature from the melt composition of K/Nb=65.0/35.0 was transparent and smooth in quality. Crystallographic relationship between single-crystalline KNbO₃ film and SrTiO₃ substrate was also investigated.