Spectral dependences of thermally stimulated luminescence and X-ray luminescence of single-crystalline and glassy Li2B4O7:Mn

Abstract

Thermally stimulated luminescence (TSL) and X-ray excited luminescence (XL) spectra of single-crystalline and glassy Li2B4O7:Mn (LTB:Mn) are studied. For single-crystalline LTB:Mn, maxima at the TSL spectral dependences at 608±2 and 598±2 nm are revealed, their position being practically unchanged in a wide range of manganese dopant concentrations and irradiation doses. In the TSL and XL spectral dependences of glassy LTB:Mn, a smeared, low-intensity peak is observed, its maximum being shifted towards longer wavelengths in comparison to single-crystalline LTB:Mn. In the LTB:Mn single crystals, manganese mostly forms point defects of a Mn type, the superfluous charge being compensated by cationic vacancy. In glassy LTB:Mn, due to the decrease in packing density of the main structural blocks and because of the decreasing [BO3] triangle to [BO4] tetrahedron ratio, some Mn2+ ions are oxidized to Mn3+, resulting in the features of the spectral characteristics of TSL.