Surface nanostructuring ofTiO2thin films by high energy ion irradiation

Abstract

The effects of a high ion dose irradiation on ${\text{TiO}}_{2}$ thin films under different conditions of temperature and ion nature are discussed. We have shown that anatase ${\text{TiO}}_{2}$ thin films irradiated with ${\text{N}}^{+}$ ions at room temperature develop a typical microstructure with mounds and voids open to the surface whereas irradiations at 700 K generate a surface pattern of well-ordered nanorods aligned with the ion beam. The formation of these patterns is caused by the simultaneous effect of ion irradiation near the film surface and a film temperature favoring the structural mobilization of the defective network of the material. To explain these phenomena, a qualitative model has been proposed and further tested by irradiating the ${\text{TiO}}_{2}$ thin films with ${\text{F}}^{+}$ and ${\text{S}}^{+}$ ions under different conditions. The obtained results demonstrate that ion irradiation techniques enable the formation of tilted nanorod surface patterns with lengths of about 100 nm on anatase ${\text{TiO}}_{2}$ thin films.