Anti-reflective coatings are essential for enhancing the efficiency of photovoltaic systems by minimizing surface reflections. In this study, TiO2 and SiO2 thin films were deposited on silicon substrates via sputtering and subsequently treated with an argon plasma jet for 5, 10, and 15 min. Optical emission spectroscopy confirmed the presence of active plasma species. Plasma treatment significantly reduced surface reflectance in the 450–750 nm range from 2.38 % to 0.59 %, 0.48 %, and 0.45 %, respectively consistent with Lumerical simulations. A concurrent decrease in refractive index was also observed. Structural analyses revealed the anatase phase prior to thermal treatment, evolving into a mixed anatase–rutile phase with enhanced crystallinity post-treatment. Moreover, plasma modification lowered surface roughness and improved coating uniformity, as confirmed by FE-SEM and AFM.
