Luminescence of Ca0.5Ba0.5Ga2S4 crystals activated by Eu2+ and Er3+ ions

The photoluminescence (PL) in the visible spectral range of Ca0.5Ba0.5Ga2S4 solid solutions activated with ions of rare-earth elements Eu2+ and Er3+ has been studied in the temperature range of 10-300 K. The PL spectrum contains a strong luminescence band peaking at 530 nm, which is due to the 4f (6)5d -> 4f (7) transitions in Eu2+ ions and weak lines in the range of 650-675 nm, which are due to the (4) F (9/2) -> (4) I (15/2) transitions in Er3+ ions. The position of the PL spectrum and the total PL intensity are characterized by high temperature stability in the range of 10-300 K; the total PL intensity decreases by only 13% with respect to the maximum value at 10 K. The PL decay time and the activation energy of nonradiative recombination channels are found to be tau (e) = 291 ns and E (a) = 41 meV, respectively.