No abstract

The crystallinity of anatase TinormalO2 material synthesized from an acidic fluoride-based solution at 60to200°C was raised by increasing the growth temperature by an amount that was significantly lower than that required by postdeposition heat-treatment in air. As higher temperatures lead to more complete dehydration reactions and lower proton incorporation, the long-range attractive forces necessary for crystallinity are disrupted to a lesser degree. In addition, films grown on glass slides at 60 and 100°C exhibited preferential c -axis orientation due to restricted lateral and off-normal growth of crystallites elongated along the c -axis. As the island nucleation density was higher at 100°C , this resulted in even less lateral and off-normal crystallite growth compared to the film grown at 60°C , giving rise to a greater degree of c -axis preferred orientation for the 100°C film.

Crystalline CeO 2 films grown in aqueous solutions at 45 • C on glass slides formed by the island growth mode. The film had a refractive index of 1.83 and indicated that the film had a porosity of 41.3%, which significantly lowered the elastic stiffness of the film. The film cracked only after drying in a mud crack pattern when it reached a critical thickness. This indicated that the film cracked under tensile stress due to the accumulation of tensile strains generated from grain coalescence during growth, thermal expansion mismatch during cooling and capillary stress during drying.