Study of properties of CuO:CR nanostructures thin film

Thin films of polycrystalline CuO were effectively synthesized on pre-cleaned glass substrates through the hydrothermal method. Both undoped and chromium-doped samples were rigorously characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), and UV–Vis spectroscopy. The results of the XRD analysis confirmed that all films displayed a monoclinic polycrystalline structure, with the doping of chromium affecting the primary crystallite reflections: (110), (002), and (111) for undoped CuO, and (110), (020), and (111) for CuO films doped with 3%, 6%, and 9% chromium. The crystallite sizes, determined using Scherrer’s formula, varied from 38.12 nm to 33.26 nm. Analysis of the UV–Vis spectra indicated that the incorporation of chromium modified both the transmittance and the energy band gap, with the Eg values escalating from 1.99 eV for undoped CuO to 3.6 eV for the 9% chromium-doped variant. The FE-SEM imagery demonstrated a smooth and uniform morphology of the films, while EDS analysis verified the presence of chromium as a dopant, along with copper and oxygen. The optical characteristics, encompassing absorbance, transmittance, and band gap energy, were significantly affected by the concentration of chromium.