Preparation of La0.5Li0.5TiO3 perovskite thin films by the sol–gel method

Abstract

Perovskite La_0.5Li_0.5TiO₃ (LLT) thin films, 0.2–1 μm thick, were deposited on non-alkali aluminoborosilicate glass substrates (NA substrates) and glass substrates with ITO (indium tin oxide) coatings (ITO substrates) by the sol–gel method. Alkoxide-based solutions containing titanium alkoxide, lithium alkoxide and lanthanum alkoxide and acetate-based solutions containing titanium alkoxide, lithium acetate and lanthanum acetate, were used as coating solutions. Impurity phases tended to be precipitated on heat treatment in the films derived from the acetate-based solutions. Addition of acetylacetone or partial substitution of lead for lithium in the acetate-based solutions, however, was effective in suppressing the precipitation of impurity phases. Preferred orientation of the LLT (1 1 1/2) plane was observed in the films prepared from the acetate-based solutions when NA substrates were used, whereas the employment of the alkoxide-based solutions or ITO substrates and the partial substitution of lead for lithium, reduced the preferred orientation. The electrical conductivity of the films was much lower than the values reported for the sintered materials.