Growth regulation of WO3 film by H2C2O4 during chemical bath deposition

In this study, a two-step chemical bath deposition-annealing process was used to fabricate WO3 films on a fluorine-doped tin oxide basement. By controlling the reactant amounts, the growth and thickness of the as-prepared H2WO4 and WO3 films can be regulated. A possible three-step growth mechanism was identified to describe the growth of H2WO4 films. The morphology, structure, and light response of the as-fabricated films were characterized by X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared diffuse-reflectance spectroscopy, among other methods. Photoluminescence spectroscopy was used to test the separation, recombination, and transportation of photogenerated carriers. The results indicate the inhibition of the photogenerated carrier recombination rate in the WO3 film with decreasing thickness.