Preparation of Ca(1−x)EuxGa2S4 crystals and their photoluminescence, absorption and excitation spectra Original Research Article

The single crystal of CaGa2S4:Eu is expected as a useful laser material with a high quantum efficiency of light emission. However, as far as our knowledge is concerned, the systematic study of the mixed compounds of Ca(1−x)EuxGa2S4 as a function of x has not been reported up to now. Here, we have first constructed the phase diagram of the CaGa2S4 and EuGa2S4 pseudo binary system, and show that it forms the solid solution. Then we have grown single crystals of these compounds. The maximum photoluminescence efficiency is achieved at x=0.25. From the three peak energies observed in the photoluminescence excitation (PLE) and absorption spectra, the 5d excited states are suggested to consist of three levels arising from the multiplets of Eu2+ ions.