ESR and TSL study of hole and electron traps in LuAG:Ce,Mg ceramic scintillator

• A joint study of ESR and TSL was performed to investigate the hole and electron traps in LuAG:Ce,Mg ceramics.
• The thermal stability of the O− centers are studied for the first time in LuAG:Ce by ESR.
• A recombination process of freed electrons from shallow electron traps (some of which are related to the antisite defects) with holes forming O− centers is proposed.
• A tunneling process between trapped electrons and randomly distributed Ce centers is revealed by TSL and phosphorescence experiments.

The process of hole and electron localization in LuAG:Ce,Mg ceramics is studied by electron spin resonance (ESR) and thermally stimulated luminescence (TSL). Hole traps, which are created by UV irradiation, are detected in the form of O− centers. Mg-perturbed variants of O− centers are proposed to exist. The thermal stability of such defects is studied, proving that they are stable up to room temperature. The interaction between O− centers and shallow electron traps is studied by thermally stimulated luminescence (TSL) and phosphorescence experiments, which reveal the occurrence of an a-thermal tunneling process between trapped electrons and randomly distributed Ce centers. By correlating the TSL-derived trap parameters and temperature dependent ESR intensities, it is found that O− centers compete with Ce centers in free electron capture.