Luminescence of undoped and Ce3+-doped Lu(Sc,Y)AG crystals

Emission and excitation spectra and decay kinetics are studied for the luminescence of undoped and Ce3+-doped LuScAG and LuYAG crystals at 10–300 K and compared with the characteristics of undoped and Ce3+-doped YAG and LuAG. Besides the Ce3+-related intense green emission bands, the intrinsic UV bands are observed. At 80 K they are located at 4.9-4.4 eV. At RT the intrinsic emission bands are located at lower energies. The positions of the lowest-energy excitation band of the intrinsic emission in all the crystals studied are different and shifted to lower energies with respect to that in LuAG (7.2 eV at 80 K). This band is ascribed to the exciton perturbed by the corresponding defect (Lu3+, Y3+, Sc3+, Ce3+). The origin of the Sc3+- and Y3+-related luminescence and the role of these ions in the processes of energy transfer from the crystal lattice to Ce3+ ions are discussed.