Abstract <p>This study investigates the properties of europium and erbium co-doped silicon oxycarbide thin films prepared by Catalytic Chemical Vapor Deposition using tetraethoxysilane, europium oxide, and erbium oxide as precursors. While maintaining a constant volume of tetraethoxysilane, varying concentrations of europium and erbium oxides were employed during deposition, allowing for a comprehensive analysis of the films’ morphology, composition, and thickness. The impact of dopant concentrations on thin film properties was evident in morphological variations induced by europium and erbium incorporation, altering chemical bonding pathways as confirmed by FTIR and XPS analyses. Ellipsometry revealed an augmented refractive index with increasing co-dopant concentrations, showing the tunability of optical properties. Photoluminescence studies unveiled a broadened emission spectrum, emphasizing synergistic interactions between europium and erbium. Furthermore, time-resolved photoluminescence indicated prolonged recombination times at higher dopant concentrations, suggesting enhanced performance in applications requiring sustained optical responses. These findings present opportunities for advancements in optoelectronic technologies.</p>