Luminescence Investigation of BaMgF4 Ceramics Under VUV Synchrotron Excitation

Abstract

The luminescence properties of BaMgF4 ceramics synthesized using electron beam-assisted synthesis were investigated under vacuum ultraviolet (VUV) synchrotron excitation at a cryogenic temperature of T = 9 K. Their excitation spectra, measured over the 4–10.8 eV range, and corresponding luminescence spectra revealed a complex multicomponent structure with emission maxima at 3.71, 3.55, 3.33, 3, and ~2.8 eV. The primary luminescence band at 330 nm was attributed to self-trapped excitons (STE) excited near the band edge (9.3–9.7 eV), indicating interband transitions and subsequent excitonic relaxation. Bands at 3 and ~2.8 eV were associated with defect states efficiently excited at 6.45 eV, 8 eV and high-energy transitions near 10.3 eV. The excitation spectrum showed distinct maxima at 5, 6.45, and 8 eV, which were interpreted as excitations of defect-related states. These results highlight the interplay between interband transitions, excitonic processes, and defect-related luminescence, which defines the complex dynamics of BaMgF4 ceramics. These findings confirm that radiation synthesis introduces defect centers influencing luminescent properties, making BaMgF4 a promising material for VUV and UV applications.