Journal of Inorganic Materials, Volume. 37, Issue 10, 1123(2022)
With its excellent comprehensive performance, Gd3(Al,Ga)5O12:Ce (GAGG:Ce) scintillation crystal has broad application prospects. To accelerate the luminescence decay rate, Mg-codoped Gd3(Al,Ga)5O12:Ce single crystals were grown by Czochralski method. The test results show that with the concentration of Mg2+ increasing, the scintillation decay of the crystal accelerates and the light output decreases. The conventional interpretation suggests that Mg2+ could convert part of Ce3+ into Ce4+ through charge compensation, and the Ce4+ luminesces more quickly. This study tries to discuss the mechanism of Mg-codoping in GAGG:Ce crystals from the perspective of antisite defect. Since the ionic radius of Ce is larger than Gd, the doping of Ce ions leads to a distortion of the crystal lattice near the luminescence center CeGd. As a result of the distortion, the space of the adjacent octahedral sites become larger, and the antisite defects are more likely to form in these larger octahedral sites. Eventually each luminescence center CeGd is surrounded by four antisite defects GdAl, which would capture carriers and delay the energy transfer from the matrix to the luminescence center. As the ionic radius of Mg is between Gd and Al, MgAl also prefers to form in those distorted octahedral sites, which inhibits the formation (or enrichment) of the antisite defect GdAl near the luminescence center CeGd, and eventually reduces (or even eliminates) the adverse effects of the antisite defect on the luminescence center. XEL results show that with the increase of Mg concentration, the emission peak related to the antisite defect becomes weaker, which indicates that Mg could inhibit the formation of the antisite defect.
Get Citation
Copy Citation Text
Mingqing LI, Linwei WANG, Dongzhou DING, He FENG.
Category: RESEARCH ARTICLE
Received: Dec. 29, 2021
Accepted: --
Published Online: Jan. 12, 2023
The Author Email: DING Dongzhou (dongzhou_ding@mail.sic.ac.cn)