Growth and scintillation properties of Sc, Pr, Ce co-doped LuAG epitaxial garnet layers

Single crystalline Sc, Pr, Ce co-doped Lu₃Al₅O₁₂ garnet layers were grown by liquid phase epitaxy. The Sc doping increases the scintillation response of Pr³⁺ activator ions because of overlap of the Sc-related emission around 275 nm with the 4f→5d absorption band of Pr³⁺ centers. The radioluminescence (RL) spectra give evidence for presumed energy transfer form Sc³⁺ to Pr³⁺ activator ions. Significant increase of the RL emission output was observed when co-doping with both Pr and Sc ions compared to Sc-free samples. The maximum integral RL was noticed for samples with relatively high Sc concentration, 1.2 - 3 at %. On the contrary, an increase of the photoelectron yield, N_phe, measured under alpha particle excitation, was observed only for rather low Sc content, ∼0.6 at %, at higher Sc concentrations N_phe decreased. Nevertheless, LuAG epitaxial layers with optimal Sc and Pr contents show comparable or even a bit higher N_phe yield and energy resolution than Cz-grown Pr:LuAG single crystals. Furthermore, the slow components in photoelectron response were significantly suppressed in epitaxial layers compared to single crystals.