120 MeV Au⁹⁺ Beam Irradiation Effects in Spin Coated Polycrystalline TiO₂ Thin Films and its Comparison with SnO₂ Thin Films

The present work reports the effects of 120 MeV Au 9+ on structural and electronic properties of polycrystalline TiO 2 films of about 435 Å thickness prepared by spin‐coating. The effects are clearly seen in the surface morphology, crystalline nature, vibration spectra, and optical measurements. The atomic force microscopy images clearly show the formation of self‐affine structure in the studied films. Further, with increasing irradiation fluence, the roughness is observed to increase, corroborating the X‐ray reflectivity measurements. With increasing fluence, amorphization is observed from grazing incidence X‐ray diffraction measurements. The optical bandgap is observed to vary with ion‐beam irradiation, presumably due to the formation of defect states due to oxygen vacancies. No significant change is observed in the oxidation state of the metal ion (Ti) in the present study. This is in contrast to our earlier results of SnO 2 thin films, [ 1 ] and the possible reason for this could be the variation of electronic energy loss values for the two cases.