Heavily Ce3+ -doped Y3Al5O12 thin films deposited by a polymer sol-gel method for fast scintillation detectors
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 Y3-xCexAl5O12 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 photoluminescent spectra are presented. The photoluminescence decays of the samples containing up to 6 at.% of cerium are comparable in radiative lifetime to Ce3+:YAG single crystals having the cerium concentration limit over one order smaller. The cathodoluminescence of samples and soft X-ray nanosecond pulse-excited decays is examined. The scintillation decays appear much faster with 1/e decay time well below 10 ns compared to a Ce3+:YAG single crystal which shows 140 ns. After further optimization of microstructure and overall scintillation yield, the sol-gel prepared Ce3+:YAG thin films are promising candidates for the application in fast SEM scintillation detectors, currently intensively prospected R&D in the scintillator technology field.