Heavily Ce3+-doped Y3Al5O12 thin films deposited by a polymer sol–gel method for fast scintillation detectors

Abstract

The performance of cerium-doped Y₃Al₅O₁₂ (Ce³⁺:YAG) often depends on cerium solubility achievable in a particular preparation technology. This solubility is kinetically affected by the synthesis process which allows for Ce³⁺ solubility to be generally much higher in a polycrystalline material than in single crystals. This work presents Y_3−xCe_xAl₅O₁₂ polycrystalline thin films deposited by spin-coating where cerium is substituted on yttrium sites in an interval of 3.3–25 at%. Up to a concentration of 18 at%, the samples remain single-phase, which is the highest Ce³⁺ doping level in YAG published so far. Absorption, excitation and emission photoluminescence spectra are presented. The photoluminescence decays of the samples containing up to 6 at% cerium are comparable in radiative lifetime to those of Ce³⁺:YAG single crystals having the cerium concentration limit over one order smaller. The cathodoluminescence of the samples and soft X-ray nanosecond pulse-excited decays are examined. The scintillation decays appear much faster with a 1/e decay time well below 10 ns compared to that of a Ce³⁺:YAG single crystal which is 140 ns. After further optimization of the microstructure and the overall scintillation yield, sol–gel prepared Ce³⁺:YAG thin films are promising candidates for application in fast SEM scintillation detectors, currently intensively investigated in the scintillator technology field.