Abstract
Gamma rays cause the alteration in charge carriers’ density of the target material which tailors the material peculiarities in a considerable manner. In the present study Zirconium oxide (ZrO2) nanocrystalline thin films of thickness 163 nm, were prepared by Radio Frequency (RF) sputtering technique followed by the exposure of various level of gamma (γ) irradiation dose (500 kGy–2000 kGy) at room temperature. The prepared thin films were examined by XRD, UV–Vis., AFM, PL, Raman, RBS, and XPS. Compared with the pristine thin film, gamma irradiated samples showed the significant changes in the structural and optical characteristics of ZrO2 thin films. After being irradiated, the shifting in monoclinic and tetragonal structure is observed towards higher diffraction angle and the crystallite size is varied from 5.8 to 11.83 nm, investigated by X-ray diffraction technique. However, the optical band gap is varied with increasing absorbed dose and calculated 4.29 eV, 3.76 eV, 3.65 eV, 3.81 eV and 3.59 eV for pristine, 500 kGy, 1000 kGy, 1500 kGy and 2000 kGy respectively by Tauc plot function. The change in surface morphology is observed from the AFM and found the remarkable change in grain size (21–52 nm). The photoluminescence analysis revealed the presence of strong characteristic green emission at 546 nm is ascribed to of 5D4 → 7F5 transition. Raman study revealed that presence of peak at 432 cm−1 belongs to M (Ag) symmetries, and the intensity of the raman bands is varied with the gamma dose. Rutherford backscattering spectrometry (RBS) has been used to investigate the thickness (163 nm) and atomic content of Zr and O (1:2) in ZrO2 thin films. Shifting of Zr 3d peaks towards lower and higher binding energy at 500 and 2000 kGy gamma irradiated thin films is validated by XPS measurements. The results indicated that ZrO2 thin films show high radiation hardness under high dose (2000 kGy) gamma-ray (60Co) radiation environment. This study reveals that gamma radiation on ZrO2 thin films play a significant role in tailoring the physio-chemical peculiarities of tin films of ZrO2 at distinct dose.
•Thin films were prepared by RF sputtering technique on Si/glass substrate.•XRD and XPS indicate the shifting of the peaks with gamma dose.•Optical analysis reveals the decrease in band gap after irradiation.•PL results showed the significant increase in intensity of green emission band.