Impact of Ni Doping on the Structural, Optical, and Magnetic Properties of ZnO Thin Films Deposited via Chemical Bath Deposition

Nickel-doped zinc oxide (Ni:ZnO) thin films were successfully synthesized on glass substrates using the chemical bath deposition (CBD) technique at 80°C. The structural, optical, and magnetic properties of the films were systematically analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) spectroscopy, and vibrating sample magnetometry (VSM). XRD patterns confirmed the formation of a hexagonal wurtzite structure in both undoped and Ni-doped ZnO samples, with no secondary phases detected, indicating successful incorporation of Ni ions into the ZnO lattice. SEM analysis revealed a variation in nanorod morphology with increasing Ni content, leading to a change in aspect ratio and surface roughness. UV-Vis spectroscopy showed a redshift in the absorption edge with increasing Ni concentration, suggesting band gap narrowing due to Ni-induced modifications in electronic states. Magnetic measurements confirmed room-temperature ferromagnetism in Ni-doped ZnO films, attributed to the exchange interactions between Ni ions and localized ZnO defects. The optimized 2% Ni-doped ZnO film exhibited enhanced structural and magnetic properties, making it a promising candidate for spintronic applications. This study provides valuable insights into the role of Ni doping in tailoring the multifunctional properties of ZnO thin films for optoelectronic and magnetic device applications.