SYSTEMATIC INVESTIGATION OF THE EFFECT OF γ RADIATION ON THE OPTICAL AND STRUCTURAL PROPERTIES OF NANOSTRUCTURES DOPED WITH IRON-ZINC OXIDE AND GROWN AT LOW TEMPERATURES

Abstract

In this paper, we present a successful synthesis of Fe-doped nanostructures (ZnO) using the aqueous chemical growth (ACG) method at low temperatures (95°C). Structural, morphological and optical properties were performed on pristine samples of zinc oxide and iron-doped zinc oxide, with iron concentrations of 5%, 10% and 15% respectively. Scanning electron microscopy (SEM) confirmed that all synthesized nanostructures have a hexagonal rod-shaped morphology; however, an increase in the concentration of Fe gradually changes the surface density and leads to agglomeration. The hexagonal crystalline phase of Wurtzit (JCPDS Map No. 36-1451) confirmed X-ray diffraction (XRD) analysis for all samples. The displacement of the diffraction peak (101) to a lower angle shows the successful addition of Fe³⁺ ions to the ZnO lattice, resulting in an increase in the distance d and a reduction in the size of the crystallite. A systematic redshift of the absorption edge and the narrowing of the optical range from 3,392 eV (5% Fe) to 3,225 eV (15% Fe) before irradiation by UV-visible spectroscopy were confirmed. Subsequently, all synthesized samples were subjected to gamma irradiation (γ) at a high dose of 500 gray using a ⁶⁰Co source at room temperature. Post-irradiation studies showed: (i) In a 15% Fe sample, a blueshift was observed at the absorption edge with area expansion to 3,503 eV; (ii) displacement of the XRD peak at angles higher than 2θ, showing the contraction of the network and the reduction of the distance d; (iii) at certain concentrations, the size of crystallite increases; and (iv) post-irradiation SEM images showed visible surface damage, melting, and destruction of the edges of the nanorods. Fe doping and irradiation γ both lead to a reduction in permeability. This showed that the structural and optical properties of Fe-ZnO can be adjusted by the concentration of dopants and the dose of ionizing radiation. This opens up possibilities for photonic and sensory device applications that harden with radiation.