Hydrothermal synthesis of potassium tantalate thin film

Abstract

Thin films of potassium tantalate have been prepared on Ta metal substrates in KOH solutions by the hydrothermal and the hydrothermal-electrochemical methods. Phase-pure perovskite-type KTaO₃ thin films could be formed in 2.0 M KOH at 300°C. Pyrochlore-type K₂Ta₂O₆ thin films were formed at lower temperatures and lower KOH concentrations. Lattice constant of the KTaO₃ was almost the same as that in JCPDS-PDF, whereas lattice constant of K₂Ta₂O₆ was 0.2% larger than the PDF value.