Characterization of silver layers deposited by aluminum oxide, silicon dioxide, and blend for highly reflective optics

This study explores the application of metallic silver coatings in optical telescopes. The silver film demonstrates high reflectance across the visible to the infrared spectral range and exhibits excellent adhesion properties. X-ray photoelectron spectroscopy (XPS) analyzes the bonding properties of the two interfaces above and below the silver layer. The main bonds identified in the silver interfaces were Ag–O, Ag–Si, and Ag–Al₂O₃. The covalent character Ag–O bond is crucial for layer adhesion, as it causes a shift to the high binding energy of Ag⁰ in the Ag3d XPS spectrum. Enhanced silver multilayers retaining their reflectance and adhesion are essential for space optics in harsh environments.