Energy transfer and charge carrier capture processes in wide-band-gap scintillators

Electron and hole trapping phenomena below room temperature were studied by simultaneous use of electron paramagnetic resonance (EPR) and thermostimulated luminescence (TSL) experiments in Ce-doped YAlO3, Y 3Al5O12 and Lu3Al5O 12 single crystals. Charge-carrier trapping associated with O - centers and antisite Y(Lu)Al defects in perovskite and garnet structures, respectively, was evidenced by EPR and associated with the dominant TSL peaks. Existence of F+ centers was proved by EPR in YAlO3. A Ce3+ ion at the Al site and spatially correlated CeLu and LuAl centers were evidenced in Lu 3Al5O12 by the same method. Spatial correlation of the latter two centers is further supported by the associated tunneling-driven radiative recombination process evidenced by phosphorescence decay.