Characterization of rare earth element doped CeO2 thin film produced by ultrasonic chemical spray pyrolysis technique

In this study, undoped and 4-8-10% La doped CeO_2thin films were obtained by spray pyrolysis (chemical spraying) method at a base temperature of 300±5 oC. The obtained films were analyzed by XRD, SEM, AFM, Raman spectroscopy, UV-Vis and photoluminescence spectrometry and FE-SEM. The obtained films were observed to have a cubic crystal structure and 20-70% transmittance in the visible region (300-900 nm). The optical band gap value of CeO_2was 3.2 eV and increased with increasing La concentration. In photoluminescence measurements, blue and green emissions were found in the films. According to FE-SEM analysis results, morphological changes such as cracks and particle agglomeration were observed in the films. Raman Spectroscopy was used to evaluate the concentration of oxygen vacancies in the films. The characteristic peak at ~ 465cm^(-1)attributed to the overlapping Raman phonon mode was observed in the fluorite structure of undoped CeO_2. The observation of variations in the peak is due to the difference in the ionic radius of the dopant species. The peak at ~500cm^(-1) in the Raman shift indicates the presence of an oxygen vacancy. In conclusion, La doping has significant effects on the crystal structure, surface morphology, chemical composition and optical properties of CeO_2 thin films. It provides important insights into the fabrication and characterization of thin films and provides a valuable basis for future research.