The central role of oxygen on H+-irradiated Lu2SiO5 luminescence

The behavior of self-trapped defects (STDs) in ion-beam irradiated Lu2SiO5 (LSO) crystal has been investigated via temperature-dependent radioluminescence (RL) measurements. Production of oxygen vacancies is the major effect of H+ irradiation on luminescencent properties of this phosphor. Luminescence centers for self-trapped exciton (STE) and self-trapped hole emission are assigned to oxygen vacancies and oxygen ions, respectively. Ion-induced structural damage modifies the thermal stability of the STDs and creates perturbed STEs. A striking effect of ion irradiation is the approximate factor-of-two enhancement of STE RL intensity that results from implantation of only a thin (∼250 nm) surface layer of LSO. This enhancement is attributed to ion-beam modification of a surface dead layer.