Results and Discussion

Abstract

Figure 4.1a shows the XRD patterns of the KN thin films grown on the Pt–Si substrate at various temperatures. An amorphous phase was formed in the films grown below 700 °C. The KNb₃O₈ and KNb₅O₁₃ phases, indicated by open circles and open triangles, respectively, were developed in the film grown at 700 °C without formation of the KN phase. Therefore, it was not possible to grow the homogeneous KN film by the sputtering method using the stoichiometric KN target owing to the evaporation of K₂O. A similar result was obtained for the NKN film; the amorphous phase was formed for the films grown at temperatures ≤500 °C, and the Na-deficient secondary phase, with a small amount of the NKN phase, was formed in the film deposited at 600 °C, due to the evaporation of K₂O and Na₂O [1,2,3].