Effect of SiN(x) diffusion barrier thickness on the structural properties and photocatalytic activity of TiO(2) films obtained by sol–gel dip coating and reactive magnetron sputtering

We investigate the effect of the thickness of the silicon nitride (SiN(x)) diffusion barrier on the structural and photocatalytic efficiency of TiO(2) films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO(2) films produced using soft chemistry (sol–gel) and physical methods (reactive sputtering) are affected differentially by the intercalating SiN(x) diffusion barrier. Increasing the thickness of the SiN(x) diffusion barrier induced a gradual decrease of the crystallite size of TiO(2) films obtained by the sol–gel process. However, TiO(2) obtained using the reactive sputtering method showed no dependence on the thickness of the SiN(x) barrier diffusion. The SiN(x) barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO(2) films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO(2) films obtained by each process was discussed.