Effect of low and relatively long-term gamma irradiation on physical properties of ZnO and ZnO:Co thin films

In this study, undoped zinc oxide and cobalt-doped thin films were deposited on glass substrates using a sol-gel dip-coating technic. The effect of gamma irradiation on structural, morphological, and optical properties of the samples was investigated. Different analyses including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, UV-Vis spectrophotometry, and photoluminescence spectroscopy (PL) were applied to evaluate the physical changes due to gamma irradiation of the 60Co gamma-ray source. Furthermore, the sensing performance of the samples toward ethylene glycol vapor was investigated before and after irradiation. The results revealed that under low and relatively long-term gamma irradiation, tangible effects on various physical properties (especially optical and sensing characteristics) can be observed. According to our data, in undoped zinc oxide, a higher sensitivity is observed (with an increase of 2.5 times), whereas in cobalt doped, the sensitivity is reduced (with a 1.8 times reduction). ZnO and ZnO:Co thin films have been prepared by the sol-gel dip coating method.Physical properties were examined by exposing to gamma irradiation for 40 days.Gamma irradiation effectively affected the optical properties of the samples.Ethylene glycol sensing of ZnO is increased by 2.5 times after irradiation.