Characteristics of TiO₂Thin Film Surfaces Treated by Helium and Air Dielectric Barrier Discharge Plasmas

Abstract

The characteristics of TiO 2 thin film surfaces treated with He and air dielectric barrier discharge (DBD) plasmas at different gas pressures are investigated. There is a difference between the two DBD plasma characteristics: for He-DBD, which is an atmospheric pressure glow discharge (APGD), the breakdown voltage and discharge current hardly change with increasing gas pressure, whereas for air-DBD, which is basically a filamentary discharge, they increase with increasing gas pressure. There is also a difference between the characteristics of TiO 2 surfaces treated with the two DBDs. The surface roughness for He-DBD is lower than the roughness of the as-grown surface, whereas that for air-DBD is higher. The surface hydrophilicity for He-DBD is more enhanced than the hydrophilicity of the as-grown surface regardless of UV irradiation. The hydrophilicity for air-DBD is dependent on UV irradiation. It is more enhanced with UV irradiation; it is not improved adequately without UV irradiation.