Synthesis and Characterization of Nickel-Doped Cerium Oxide Thin Films Using Solution Growth Technique

Metal-doped rare-earth oxides thin films, synthesized via solution growth, enable tunable electronic, optical, and catalytic properties for diverse technological applications due to their controlled composition and morphology. This study investigates the synthesis and characterization of Cerium Oxide (CeO₂) thin films doped with Nickel Oxide (NiO) using the Chemical Bath Deposition (CBD) technique. Reaction baths were prepared from solutions containing Cerium Nitrate, Nickel Sulphate, Sodium Hydroxide, Ammonia, and distilled water. The process involved the preparation of six reaction baths—three using Sodium Hydroxide and three using Ammonia as complexing agents, with varying concentrations of Cerium Nitrate. The deposited films were characterized for their optical and morphological properties. Optical measurements were conducted using a UV-spectrophotometer, revealing that Sodium Hydroxide resulted in lower transmittance and band gap energy compared to Ammonia at concentrations, indicating potential defects or impurities in the cerium oxide matrix. An increase in molar concentration corresponded with an elevated band gap energy, while the incorporation of NiO as a dopant significantly enhanced the band gap of the CeO₂ films. Morphological analysis via Scanning Electron Microscopy (SEM) demonstrated improved uniformity and orientation of the films with well-defined grain boundaries and reduced agglomeration when complexing agents were employed. These findings suggest that NiO-doped CeO₂ thin films exhibit promising potential for applications in photovoltaic systems, thermal control coatings, and UV radiation suppression