Luminescence and defects creation in Ce³⁺‐doped Lu₃Al₅O₁₂ crystals

Abstract

PACS 78.55.Hx, 78.60.Kn Luminescence, energy transfer and defects creation processes were studied at 4.2 -300 K for Ce 3+ -doped Lu 3 Al 5 O 12 crystals under excitation in the 2.5 -11.5 eV energy range. The results obtained were compared with the characteristics of Y 3 Al 5 O 12 : Ce crystals. It was concluded that in both systems the efficiency of energy transfer from the host lattice to the impurity ion can be noticeably increased by the decrease of concentration of the defects responsible for their intrinsic luminescence. The origin of the optically created defects and possible mechanisms of their formation are discussed.

Luminescence of dimer lead centers in aluminium perovskites and garnets

“…The steady-state emission and excitation spectra and temperature dependences of the emission intensity were measured in the 80-350 K temperature range under selective excitation in the 2.4-6.0 eV energy range at the set-up described in [3,17] and consisting of a deuterium DDS-400 lamp, two monochromators (SF-4 and SPM-1) and photomultiplier (FEU-39 or FEU-79) with an amplifier and recorder. The spectra were corrected for the spectral distribution of the excitation light, the transmission and dispersion of the monochromators and spectral sensitivity of the detectors used.…”

“…8a) can arise from the electronic transitions from the emitting minima of the triplet excited state of the Pb 2+ ion. In Ce 3+ -and Pr 3+ -doped SCF, where the decay time of the fast component is close to the decay times of the Ce 3+ and Pr 3+ emissions, the relatively intense fast component can mainly arise from the overlap of the ≈3.2 eV emission studied with the UV emissions of Ce 3+ or Pr 3+ centers (see, e.g., [3,21]). The decay time values exhibit a continuous decrease with an increasing temperature (down to 250 ns and 50 ns at RT in the LuAG:Pb ceramics).…”

“…1 Introduction Single crystals of lutetium-aluminium garnet Lu 3 Al 5 O 12 (LuAG), yttrium-aluminium garnet Y 3 Al 5 O 12 (YAG), lutetium-aluminium perovskite LuAlO 3 (LuAP), and yttrium-aluminium perovskite YAlO 3 (YAP), doped with Ce 3+ ions, have a high density and excellent mechanical and chemical stability, possess an intense and fast emission due to 5d-4f radiative transition of Ce 3+ and have been, thus, considered for fast scintillator applications (see, e.g., [1][2][3][4]). Under excitation of the undoped, meltgrown bulk single crystals (SC) in the band-to-band and exciton energy range, an intense complex slow intrinsic luminescence was observed in the UV spectral range.…”

Strong visible and near infrared luminescence in undoped YAG single crystals

“…2 The luminescence of undoped YAG crystals has been extensively studied. [8][9][10][11][12][13][14][15] However, most of the measurements have focused on the UV emission and identified it as the main luminescence in the YAG structure and the main defect center that compete with Ce 3+ ion in Ce doped YAG (Ce:YAG) scintillators.…”

“…16 However according to the current measurements, undoped YAG has multiple strong luminescence peaks, not only the 300 nm emission, which has been the focus of all the previous investigations on YAG crystals. [6][7][8][9][10][11][12][13][14][15][16] The UV emission in YAG has been suggested to result from self trapped excitons and antisite defects Y Al 3+ , 16 which have low formation energy as predicted by first principals calculations. 17 We attribute the new observed PL emission bands at 700 and 800 nm to Fe 3+ impurities for the following reasons: 1) Fe 3+ in either tetrahedral or octahedral sites has a broad emission in many materials between 700 nm 1000 nm; 18 and according to EPR studies, 19 Fe ion substitutes for the Al ion at both octahedral and tetrahedral sites in the YAG structure.…”