Energy Transfer and Scintillation Properties of <formula formulatype="inline"><tex Notation="TeX">${\hbox{Ce}}^{3+}$</tex></formula> Doped <formula formulatype="inline"><tex Notation="TeX">${\hbox{(LuYGd)}}_{3}$</tex></formula><formula formulatype="inline"><tex Notation="TeX">${\hbox{(AlGa)}}_{5}{\hbox{O}}_{12}$</tex> </formula> Multicomponent Garnets

Abstract

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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> to activator Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> ions was evidenced. At low Gd doping, , two virtually independent emission centers coexist, which compete for intensity: Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> with fast 5d-4f emission and Gd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> with slow 4f-4f emission. At higher Gd concentrations, the Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> emission retrieves intensity due to the energy transferred from Gd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> donors. At Gd concentration ~ 50% and above, the Gd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> emission is suppressed due to energy migration and transfer to Ce <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> 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.