Abstract: The TiO₂nanoparticle thin films have been sensitized in situ with CdSnanoparticles. The SPSmeasurement showed that large surface state density was present on the TiO₂nanoparticles and the surface state can be efficiently decreased by sensitization as well as selecting suitable heat treatment. Both the photocurrent response and the charge recombination kinetics in TiO₂thin films were strongly influenced by trapping/detrapping of surface states. The slow photocurrent response of TiO₂nanoparticulate thin films upon the illumination was attributed to the trap saturation effects. The semiconductor sensitization made the slow photoresponse disappeared and the steadystate photocurrent value increased drastically, which suggested that the sensitization of TiO₂thin films with CdScould get a better charge separation and provide a simple alternative to minimize the effect of surface state on the photocurrent response.

Key words: CdS, Sensitization, TiO₂nanoparticulate thin films, Photoinduced carrier transport