Raman Spectroscopy and Optical Properties of CeO<sub>2</sub>:Al<sub>2</sub>O<sub>3</sub> Nanocomposites Synthesized by Pulsed Laser Deposition

This study investigated the effects of laser energy on the phase-change mechanism, optical properties, and structure of CeO2:Al2O3 nanoparticles synthesized via pulsed laser deposition (PLD). The study employed Raman spectroscopy, UV-Vis spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), and field emission scanning electron microscopy (FESEM). The process techniques were compared at different laser pulse intensities (530, 730, and 930 mJ). Porous silicon (PS) substrates have been created using the photoelectrochemical etching of n-type silicon. The XRD results for CeO2:Al2O3 nanoparticles indicated a polycrystalline cubic phase. Raman spectroscopy of CeO2:Al2O3 revealed weak peaks at around 615 and 1311 cm–1 and major peaks at approximately 452, 519, and 979 cm–1, with their intensities increasing with laser energy. The RMS surface roughness increases with increasing laser energy. The majority of nanocomposites feature spherical nanostructures that are randomly distributed and increase in size with increasing laser power. The optical bandgap of CeO2:Al2O3 thin films was determined to be 2.36, 2.62, and 2.66 eV for the varying laser energies. The quantum confinement effect caused the energy gap to widen as the laser pulse energy grew. Cerium oxide significantly contributes to the results and is chosen over traditional materials in nanocomposites because it enhances the properties of the base materials and makes them more stable when deposited at high temperatures, as observed in this work. It is also used in optical applications and a variety of other applications.