Investigation on surface states of TiO2 nanoparticulate film

TiO2 nanoparticulate films were prepared by means of Plasma-enhanced Chemical Vapor Deposition (PECVD), By further surface treatment by TiCl4 or O-2 plasma, films with different surface properties were obtained. It was found that treatment by TiCl4 plasma enhanced the amount of Ti3+ surface state and Ti dislocation of the film, detected by the surface photovoltage spectroscopy, while O-2 plasma surface treating enhanced its amount of O2- surface state. It was also indicated by the H2O adsorption experiment that film treated by O-2 plasma had larger separation efficiency for photogenerated carriers than the one treated by TiCl4 plasma.