Luminescent and scintillation properties of Ce3+ doped Ca2RMgScSi3O12 (R = Y, Lu) single crystalline films

The work is dedicated to the growth and investigation of the luminescent and scintillation properties of single crystalline films (SCFs) of Ca2−xR1+xMg1+xSc1−xSi3O12:Ce (R = Y, Lu) mixed garnets with x = 0-0.25, grown using the liquid phase epitaxy method onto Y3Al5O12 substrates from PbO-B2O3 based flux. The absorption, luminescent and scintillation properties of Ca2−xY1+x Mg1+xSc1−xSi3O12:Ce and Ca2−xLu1+xMg1+xSc1−xSi3O12:Ce SCFs with x = 0 and 0.25 were investigated and compared with the reference YAG:Ce and LuAG:Ce SCFs. Using the Ca2+, Mg2+ and Si4+ alloying, the Ce3+ emission spectra in Ca2−xR1+xMg1+xSc1−xSi3O12:Ce (R = Y, Lu; x = 0-0.25) SCFs can be notably extended in the red range in comparison with YAG:Ce and LuAG:Ce SCFs due to the increase of crystal field strength and Ce3+ multicenter creation in the dodecahedral positions of the lattices of these mixed garnet compounds. Due to the formation of Ce4+ ions, the as-grown Ca2−x R1+xMg1+xSc1−xSi3O12:Ce (R = Y, Lu) SCFs at x = 0 and 0.25 show relatively low light yield. However, after annealing in reducing atmosphere (95% N2 + 5% H2) at T > 1000 °C, a recharging Ce4+→Ce3+ takes place. After that, these SCFs possess the light yield about of 30% and 31% in comparison with the reference YAG:Ce and LuAG:Ce SCFs, respectively, and a fast scintillation response with the decay times in the ns range under α-particles excitation by 239Pu (5.15 MeV) source.