Role of Yttrium in Thermoluminescence of LYSO:Ce Crystals
Lu Chen, Dongzhou Ding, Mauro Fasoli, Tiantian Wang, Xiaopu Chen, Shuwen Zhao, Jie Chen, Yi‐Yang Sun, Jiang Li, Yuntao Wu, Feng He
Abstract
This paper presents a detailed study of the influence of yttrium (Y) concentration on thermally stimulated luminescence (TSL) of LYSO:Ce crystals and establishes the relationship between electron traps and scintillation properties. With the increase of Y concentration, the glow curve shifts toward higher temperatures and the trap depth increases gradually. Our results revealed two groups of electron traps with one shallow (Et ≈ 0.10–0.26 eV) and one deep (Et ≈ 1.00–1.21 eV). Our TSL results suggest that the amount of shallow traps varied with Y content has a positive correlation with energy resolution, while the amount of deep traps is inversely proportional to light output. In order to analyze the variation trend of trap depths and their mechanism in detail, we calculated the band gap with the PBE functional and VUV excitation spectra. The results show that the increase of band gap possibly leads to the increase of deep electron trap depth.