MeV ion irradiation induced evolution of morphological, structural and optical properties of nanostructured SnO2 thin films

Nanostructured SnO2 thin films were prepared by carbothermal evaporation method. Morphological, structural and optical properties of the SnO2 thin films, before and after 8 MeV Si ion irradiation to fluences varying from 1 x 10(13) to 1 x 10(15) ions cm(-2), were well characterized using atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), Raman spectroscopy and photoluminescence spectroscopy (PL). XRD studies revealed the presence of SnO2 and Sn nanoparticles in the as-deposited samples. AFM and FESEM studies on the irradiated samples revealed formation of nanoring-like structures, at a fluence of 1 x 10(15) ions cm(-2), with a central hole and circular rim consisting of nearly monodisperse SnO2 nanoparticles. PL studies revealed strong enhancement in UV emissions upon 8 MeV Si ion irradiation. A growth mechanism underlying the formation of SnO2 nanorings involving self-assembly of SnO2 nanoparticles around nanoholes is tentatively proposed.