MOD法により作製したTiO₂分散型VO_x薄膜の特性評価

抄録

TiO₂-V₂O₅ precursor films with a variety of molar ratio of Ti to V (x_m = 0∼35%) were fabricated by metal-organic decomposition (MOD). These precursor films were fired in O₂ atmosphere. It was found that TiO₂ nanoparticles coexisted with V₂O₅ from the measurement of XRD and SEM, and that the obtained films were TiO₂-dispersed V₂O₅ films. Precipitates of TiO₂ were observed on the surfaces of the films for x_m higher than 10%. Atomic ratio of Ti (x_a) dissolved in V₂O₅ grains as TiO₂ nanoparticles increased with increasing x_m and saturated in a range of x_a = 12-13%. For the films fabricated with x_m higher than 10%, TiO₂ precipitated on and/or between the grains. Then, these films were thermally reduced by a heat treatment under a pressure of 1.2 Pa (air). The R-T characteristics of the films indicated the phase transition due to a VO₂(M) phase. The resistance change and the hysteresis loop width decreased with increasing x_m and the suppressed R-T characteristics were obtained.