Synthesis of Nano-Crystalline Potassium Tantalate Thin Film by Hydrothermal Electrodeposition

抄録

KTaO₃ thin films have been synthesized on single crystal SrTiO₃ substrate with La_0.7Sr_0.3MnO₃ buffer layer (LSMO/STO) by hydrothermal electrodeposition at 80-110°C. At first, the preparation of KTaO₃ powder was investigated under hydrothermal condition. As a result, the powders consisting of single phase KTaO₃ were prepared in high concentration KOH solution of 18.5 M at temperature higher than 80°C. Under this condition, KTaO₃ thin film was grown on LSMO/STO substrate by hydrothermal electrodeposition. The only (l00) peaks of cubic KTaO₃ were observed in XRD patterns of KTaO₃ thin film grown on LSMO/STO substrate, suggesting the (100) orientation. The KTaO₃ (200) peak appeared at 45.39-45.52° and shifted to lower degree side with increasing film thickness. The film growth started from the deposition of fine and cubic particles (ca. 10 nm). Then the fine particles were united to form larger and flat crystallites (ca. 400 nm). Interestingly, KTaO₃ film was deposited on both positive and negative electrodes, but the growth mode was slightly different from each other.