On low-temperature luminescence quenching in Gd₃(Ga,Al)₅O₁₂:Ce crystals

Temperature dependences of the photoluminescence and X-ray excited luminescence intensity and thermally stimulated luminescence glow curves are measured in the 4.2–300 K temperature range for the undoped and Ce³⁺ - doped Gd₃(Ga,Al)₅O₁₂ crystals. The conclusion is made that no low-temperature quenching of the Ce³⁺ - related photoluminescence takes place. In both the undoped and the Ce³⁺ - doped crystals, temperature dependences of the X-ray excited recombination luminescence intensity correlate with the position and shape of thermally stimulated luminescence glow curve peaks of the hole origin. Low-temperature quenching of the X-ray excited luminescence in these crystals is explained by the fact that at low temperatures, free holes are trapped at oxygen ions while electrons are trapped at various intrinsic defects. In Ce³⁺ - doped Gd₃(Ga,Al)₅O₁₂ crystals, thermally stimulated release of the trapped holes and electrons and their subsequent recombination at Ce³⁺ ions result in the enhancement of the Ce³⁺ - related electron recombination luminescence with the increasing temperature in the 10–180 K range.