抄録
Current-voltage characteristics of TiO2 and TiO2-BaTiO3 films produced by flame spraying were measured. It was found that the film of TiO2 had semi-conductivity. Various kinds of semiconductive films having various resistivities and other properties were obtained by heat-treatment of TiO2 with which BaTiO3 had been blended in various ratios.
The resistivity of the composite films was higher than that of single TiO2. When a proper electrode was applied to the surface of a film thus produded, there would be a diode between the electrode and the substrate which served as an opposite electrode.
The effect of thickness of the films on current-voltage characteristics was considerably great; commutating ratio was rapidly decreased with the increase in thickness of the films.
It was also found that the effect of electrode was very little; very similar results were given by fired-on silver electrode and flame-sprayed metal electrodes (such as Cu and Al).
The backword current was lower with the rise of ambient temperature up to 250°C. The mechanism of commutation was considered to be attributed to the gradient of oxygen concentration in the films.
The highest commutating ratio ever obtained was as low as 95; but the value will be further raised by some proper surface treatments.
