Unveiling the role of preheating temperatures on structural, morphological, and optoelectronic properties in CeO₂ thin films

This study investigates cerium oxide thin films deposited on glass substrates using the sol-gel spin coating method, focusing on the effects of varying preheating temperatures. X-ray diffraction and Raman analysis confirms cubic crystal structure and characteristic F_2g mode respectively. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis demonstrate enhanced surface uniformity and smoothness with preheating temperatures from 200 °C to 300 °C. The films exhibit high optical transparency with slight variation in energy gaps (3.54–3.60 eV), and reduced Urbach energy with increase in preheating temperature. Density functional calculations were used to align band gap values with experimental findings and provide insights into the orbital contributions. Photoluminescence spectra reveal emission peaks between 350 and 500 nm, with peak intensities decreasing at higher preheating temperatures. These results demonstrate that adjusting preheating temperatures can effectively tailor the properties of cerium oxide thin films for applications requiring precise defect engineering.