Structural Properties of (Sn1−xMgxO) Thin Films and Optical Parameter Dependence with Gamma Ray Irradiation
Tin-Magnesium oxide (Sn1−xMgxO) thin films were prepared on glass substrates using the chemical spray pyrolysis technique, whereupon the samples were irradiated by gamma rays using a Co-60 radioactive source. X-ray diffraction showed that all prepared films were polycrystalline in nature with a tetragonal structure and a preferential growth of crystallites in the (110) plane. In general, the average crystallite size, lattice constants, dislocation density and crystallite density decreased with increasing Mg doping from 0% to 8%. Further, atomic force microscopy showed that the thin films were smooth and homogenous. The optical properties were obtained by ultraviolet–visible spectrophotometry, and the transmittance and absorbance spectra before and after gamma ray irradiation were compared for all samples, whereby the absorption and extinction coefficients and real and imaginary parts of the dielectric were studied before and after irradiation. It was found that the energy band gap values decreased from 3.94 eV to 3.72 eV with increasing Mg doping from 0% to 8% before irradiation, and from 3.92 eV to 3.59 eV after irradiation. All optical constants increased with doping percentage before and after irradiation. Energy-dispersive x-ray spectroscopy showed that all structures contained Sn and O elements in the undoped state, and contained SnO2 and Mg in the doped state.