Analysis of optical and structural properties of ZnO under the influence of gamma rays

ZnO films deposited on glass and silicon by the cathodic erosion technique, under different deposition power conditions, have been irradiated by gamma radiation from a ¹³⁷Cs source, in a relatively long exposure. This has generated an important effect on the structural and optical properties, which have been measured by XRD and by UV-Vis and Raman Spectroscopy. The effect on the bandgap width is decisively observed, which is typically found around 3.3 eV. Under the effects of irradiation, the bandwidth increases to an average value of 3.9 eV, for all cases, and in turn, a predominant orientation of the typical hexagonal ZnO structure in the (222) direction is apparently obtained. This effect has been previously seen in nanoscopic ZnO powders for gamma ray irradiation effects. (author)