Stability and electronic properties of O vacancies and Ce~(4+) in Lu_2SiO_5 tuned by C doping

摘要

Lu2SiO5:Ce is a well-known scintillator with high density, high light yield, and short decay time. Oxygen vacancies and Ce4+ have been demonstrated to degrade the scintillating properties. We investigate the effect of C doping on the stability and electronic properties of the oxygen vacancies and the Ce4+ in Lu2SiO5. Stability of the C atom at the O site and the interstitial site depends on the O chemical potential. The C defects have strong interaction with nearby oxygen vacancies and Ce4+. Importantly, C doping can tune the amount of the oxygen vacancies and Ce4+ in Lu2SiO5. C doping introduces defect bands in the band gap of Lu2SiO5 with the energies ranging from 0.13 eV to 2.1 eV above the valence band maximum.