Structural, optical and electrical properties of gamma irradiated SnO thin films

Present study reports the effect of gamma (γ-) irradiation of various doses in the range of 10-200 kGy on SnO thin films prepared by conventional reactive thermal evaporation and characterized by X-ray diffraction (XRD), Raman spectroscopy, and Hall Effect measurement. XRD patterns of the irradiated films upto 100 kGy show the improvement of crystallinity. This is evident from the strong increase in the peak intensities corresponding to (001), (101) planes of tetragonal SnO structure. Higher doses result in reduction in crystalline nature. While Raman spectra depict the phase purity of the films, the transmittance decreases due to the formation of color centers. The optical bandgap decreases from 2.91 eV to 2.7 eV as the dose increases. The electrical properties from I-V characteristics showed a decrease in resistance with the increase in radiation dose. This study shows that the defects produced by the γ-irradiation plays a major role in the optical and electrical properties of the film. The possible mechanism of the irradiation induced effect is discussed.