Microscopy Studies of Sol-Gel Derived Lithium Niobate

Lithium niobate prepared by sol-gel techniques can crystallize at temperatures as low as 200°C, and achieve a high homogeneity. In this sutdy, nucleation, crystallization, and morphological development are examined by TEM for alkoxide derived LiNbO3. Preliminary studies show that the as-dried gel is completely amorphous and homogeneous. Between 150-200°C, crystallization begins with crystallites on the order of 10-20 nm appearing in the amorphous matrix. By 450°C, single crystal spheroidal particles (0.05–0.2 μm) form. By 600°C, facetted large crystallites on the order of 1 gtm develop. Grain size and porosity are strongly dependent on the amount of water of hydrolysis in thin films.