Structural Analysis of Erbium-Doped Silica-Based Glass-Ceramics Using Anomalous and Small-Angle X-Ray Scattering

This study employs advanced structural characterization techniques, including anomalous small-angle X-ray scattering (ASAXS), small-angle X-ray scattering (SAXS), and X-ray photoelectron spectroscopy (XPS), to investigate erbium (Er3+)-doped silica-based glass-ceramic thin films synthesized via the sol–gel method. This research examines the SiO2-TiO2 and SiO2-TiO2-PO2.5 systems, focusing on the formation, dispersion, and structural integration of Er3+-containing nanocrystals within the amorphous matrix under different thermal treatments. Synchrotron radiation tuned to the LIII absorption edge of erbium enabled ASAXS measurements, providing element-specific details about the localization of Er3+ ions. The findings confirm their migration into crystalline phases, such as erbium phosphate (EPO) and erbium titanate (ETO). SAXS and Guinier analysis quantified nanocrystal sizes, revealing trends influenced by their composition and heat treatment. Complementary XPS analysis of the Er 5p core-level states provided detailed information on the chemical and electronic environment of the Er3+ ions, confirming their stabilization within the crystalline structure. Transmission electron microscopy (TEM) highlighted the nanoscale morphology, verifying the aggregation of Er3+ ions into well-defined nanocrystals. The results offer a deeper understanding of their size, distribution, and interaction with the surrounding matrix.