Radio-photoluminescence observed in non-doped Mg2SiO4 single crystal

The aim of this research is to investigate radiation-induced luminescence of non-doped Mg2SiO4 single crystal. The Mg2SiO4 single crystals were synthesized by the Czochralski process. The obtained crystal samples were studied to characterize the radio-photoluminescence (RPL), radio-luminescence (RL), and thermally-stimulated luminescence (TSL) properties. A non-irradiated (or as-prepared) sample shows no particular PL features whereas X-ray treated sample shows a broad PL emission around 630 nm under excitation at 270 nm. The latter observation indicates that RPL centre has been generated by X-ray irradiation. The X-ray induced RL can be observed due to the RPL centre around 630 nm, and the intensity monotonically increases with accumulating the incident radiation dose. TSL glow curve consists of three peaks at 160, 260, and 390 °C, and the initial rise method derived the activation energies of 1.33, 1.47, and 1.85 eV, respectively. The first two TSL are associated with some shallow trapping centres, and annealing at this temperature range builds up the RPL response. On the other hand, annealing at higher temperatures supresses the RPL response; thus, the RPL centre is located at deeper site.