Preparation of potassium tantalate niobate thin films by chemical solution deposition and their characterization

Potassium tantalate niobate (KTaxNb1−xO3, (KTN), where x = 0, 0.21, 0.36, 0.53, 0.74, 0.82, 0.86, and 1) thin films of perovskite structure were prepared by chemical solution deposition (CSD) on Si and SiO2 glass substrates. A homogeneous and stable precursor solution was obtained by dissolving potassium, niobium and tantalum isobutoxides in absolute isobutanol and an addition of diethanolamine as a modifier. The film quality was determined by annealing temperature and heating regime, Al2O3 “chemical” buffer layer and KNbO3 seeding layer. Optimum conditions for film preparation were found. It was approved by X-ray diffraction (XRD) that the films have the wanted pseudocubic perovskite structure. Infrared transmittance was measured for broad range of Ta/Nb ratios. The spectra show continuous transformation from KTaO3 to KNbO3 and indicate that the optical axis lies in the plane of the film.