Energy Transfer and Scintillation Properties of ${\hbox{Ce}}^{3+}$ Doped ${\hbox{(LuYGd)}}_{3}$${\hbox{(AlGa)}}_{5}{\hbox{O}}_{12}$ Multicomponent Garnets

Photoluminescence, X-ray excited radioluminescence and photoelectron yield characteristics were studied in multicomponent GdGaYAG:Ce and GdGaLuAG:Ce garnet films grown by liquid phase epitaxy. Nonradiative energy transfer from Gd
³⁺
to activator Ce
³⁺
ions was evidenced. At low Gd doping, , two virtually independent emission centers coexist, which compete for intensity: Ce
³⁺
with fast 5d-4f emission and Gd
³⁺
with slow 4f-4f emission. At higher Gd concentrations, the Ce
³⁺
emission retrieves intensity due to the energy transferred from Gd
³⁺
donors. At Gd concentration ~ 50% and above, the Gd
³⁺
emission is suppressed due to energy migration and transfer to Ce
³⁺
centers. In these samples, the host emission is also completely quenched and the best scintillator performance is achieved. Contrary to melt-grown crystals, no positive role of Ga substitution was found in epitaxial films.