Formation of TiO2(B) Nanocrystallites in Sol‐Gel‐Derived SiO2‐TiO2 Film

TiO 2 (B), one of the polymorphs of TiO 2 , has been formed by annealing a sol‐gel‐derived SiO 2 ‐TiO 2 amorphous film on a silicon wafer at 900°C in air. Transmission electron microscopy (TEM) revealed that nanocrystallites with a size of 5‐10 nm were dispersed in the amorphous SiO 2 matrix in the film. The X‐ray diffraction pattern and lattice fringe spacing in high‐resolution TEM images corresponded to those of TiO 2 (B). These TiO 2 (B) nanocrystallites are probably stable with the presence of surrounding SiO 2 in the film at 900°C, because previous works reported that this phase should be converted to anatase at temperatures higher than 550‐700°C.