Effect of Ni and Au ion irradiations on structural and optical properties of nanocrystalline Sb-doped SnO2 thin films

The effect of shift heavy ion irradiations on the structural and optical properties of 6 % Sb-doped SnO2 thin films deposited on quartz substrate by electron beam evaporation technique is presented. Two ion species Ni and Au with energy 120 MeV and fluence of 1 x 10(13) ion/cm(2) were used. These films were characterized by X-ray diffraction, atomic force microscope, UV-visible and micro-Raman spectroscopy. From structural analysis, these films exhibit tetragonal rutile structure and retain it even after irradiation. The ion irradiations have shown improvement in the structural properties, such as increase in grain size and decrease in the lattice strain. Raman study also indicates enhancement in quality of crystal structure after irradiations. The grain growth after ion interaction is also observed by atomic force microscope study. Further, a variation in optical band gap and reduction in disorder is observed after irradiation. Other parameters such as Urbach tails energy and steepness parameter are obtained from optical data. The overall observed physical properties show a significant improvement after irradiation. A good correspondence between structures with its various properties can be seen.