Effect of gamma irradiation on structural, morphological, optical and thermal properties of Ca doped CuO nanostructure thin films

Semiconductor optoelectronic and photonic devices are used in many harsh environment applications such as space and nuclear reactor etc. Gamma radiation in such environments significantly interacts with the semiconductor materials used in these devices, changing their structural, optical, morphological and thermal properties. Therefore, it is vital to investigate the gamma radiation effect of the material to be exposed to radiation in terms of the performance and lifetime of the application. In this study, nanostructured thin films were produced by doping different ratios (0, 0.3, 1.25, 2.5 and 5 mg/mL) of Ca to the copper oxide (CuO) is a semiconductor used in optoelectronic and photonic devices. The thin films produced were deposited on the glass substrate by the spin coating method. The effects of gamma rays on the structural, morphological, optical and thermal properties of the films were investigated by irradiating with different doses (1, 5, 15, 50, 100 and 150 kGy) used a Cobalt-60 gamma radiation source. The structural, morphological, optical and thermal properties of Ca doped CuO nanostructured thin films were investigated by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), atomic force microscope (AFM), mechanical profilometer, UV-Vis spectrophotometry (UV-Vis) and thermogravimetric differential thermal analyzer (TG/DTA). The band gap of thin films were been calculated using Tauc's plot. The obtained results showed that high-dose gamma radiation caused defects in undoped and Ca doped CuO nanostructured thin films and affected their structural, morphological, thermal and optical properties. Despite the resulting defects, Ca doped CuO nanostructured thin films showed higher absorption intensity and thermal stability against gamma rays. These results showed that Ca doped CuO nanostructured thin films are suitable for many harsh environment applications such as space and nuclear reactors.