Electron Microscopy and Diffraction Studies of the Structure of Amorphous WO3 Film

High-resolution electron-microscopic observation and analysis of the amorphous halos in electron diffraction have been carried out on WO3 film prepared by vacuum deposition. Crossed fringes forming a region about 1 nm in size are frequently seen in the micrographs, and each of their spacings corresponds to that of the lattice spacing of the WO3 crystal. On tilting the film, the lattice fringes in some regions disappeared and new fringes appeared at different positions. This shows that the micro-crystallites are distributed at random in the film. The experimental electron diffraction intensity is explained by a micro-crystal model in which microcrystallites are distributed at random with sizes of 0.8, 1.0 and 1.2 nm at ratios of 23, 54 and 23%, respectively.