Time-resolved photoluminescence spectroscopy of Ce:Gd 3 Al 2 Ga 3 O 12 crystals

Time-resolved photoluminescence (PL) spectra of Ce-doped Gd 3 Al 2 Ga 3 O 12 (Ce:GAGG) crystal have been measured at various temperatures under Ce 3+ 4f → 5d excitation. All time-resolved PL spectra show only a Ce 3+ 5d → 4f band around 2.3 eV. Decay curves of this band consist of a fast and slow components. The temperature dependence of integrated intensities of the fast and slow components are analyzed by considering nonradiative processes starting from the ground level of an electron trap. From the results of analysis, we discuss relaxation processes of 5d electrons created under Ce 3+ 4f → 5d excitation.