Optical, luminescence and scintillation characteristics of Gd3Sc2(Al3-xGax)O12: Ce,Mg (x = 0, 1, 2) single crystalline films

Optical, luminescence and scintillation characteristics of Ce3+ - doped Gd3Sc2(Al3-xGax)O12 (x = 0, 1, 2) single crystalline films fabricated by the liquid phase epitaxy (LPE) technique are investigated. A blue shift of the photo- and radio-luminescence spectra is observed as Ga content increased due to a decrease in crystal field splitting of the Ce3+ 5d levels. Temperature-dependent characteristics of radioluminescence (RL) intensity and photoluminescence (PL) decay time are investigated. At room temperature, the decrease of PL- & RL- intensity and PL decay time with increasing Ga content can be explained by thermal ionization of the Ce3+ 5d1 excited state. Gd3Sc2Al2GaO12:Ce exhibits the highest light yield (LYα) value of 1010 ph/MeV along with fast scintillation decay time of 12 ns (27%) + 52 ns (73%) under excitation with 5.5 MeV α – particles. Shortening of scintillation decay time with a decrease of the LY value is also obtained in Mg2+-codoped samples.