DOI: https://doi.org/10.55373/mjchem.v27i3.306

Keywords: Cobalt doped NiO; thin films; Annealing temperature; Surface morphology; Grain growth

Abstract

The main objective of the work is to study the structural, optical, and electronic properties of Cobalt (Co) doped nickel oxide (NiO) thin films synthesised using an efficient chelating approach method. In the present work, 5% Co is doped onto NiO using the sol-gel method with citric acid as a chelating agent and a spin-coated thin film preparation method. The synthesised Co-doped NiO thin film is characterized using Diffuse reflectance spectra (DRS) UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. The texture coefficient, Tc(hkl) provides insight into the synthesized thin films crystallographic orientation. O 1s, Ni 2p and Co 2p core-level spectra, of the Co-doped NiO sample were analyzed using the XPS spectra. The O 1s spectra indicated the presence of lattice oxygen, surface hydroxyl groups, and nickel oxides, with a notable reduction in surface hydroxylation at a selected temperature. UV-Visible spectroscopy indicates; thin film thickness is dependent on annealing temperature. Further, Tauc plots of (αhν)² yielded energy band gap values ranging from 3.70 eV for pure NiO to 3.50 eV for 5% Co-doped NiO, indicating a reduction in the band gap with Co doping. This work will impart to the metal oxide layers-based optoelectranic, medical and drug delivery applications.