H2S modified atomic layer deposition process for photocatalytic TiO2 thin films

Abstract

H₂S modified TiO₂ films were grown by atomic layer deposition (ALD) using TiCl₄, H₂S and water as precursors. The films were characterized by XRD, XPS, TOF-SIMS, SEM and UV-VIS spectrometry. Photocatalytic activities of the films under UV and visible light were determined by the degradation of a thin layer of stearic acid. Light induced superhydrophilicity of the films was also studied. Although the sulfur content of the films was very low, substantial modification of the film properties occurred. All the films prepared at 400 and 500 °C with H₂S were photocatalytically active under visible light. Photocatalytic activity under UV irradiation of the H₂S modified films was also drastically improved when proper deposition parameters were applied.