Optical properties of Sr1−xEuxGa2S4 mixed compounds

The mixed crystal system of CaGa2S4-EuGa2S4 has already been investigated and confirmed to form the solid solution. In this report, the same procedure of the previous report is applied to the SrGa2S4-EuGa2S4 system using differential thermal analysis and X-ray diffraction. It is shown that the solid solution is also formed in this system. Photoluminescence spectra of the present system have a broad-wavelength peak characteristic of the phonon-terminated 5d-4f transitions. The peak energy of the emission shifts to the low-energy side as x increases. The maximum intensity of the emission is attained at 10 mol% as about four times larger in magnitude than the emission of a stoichiometric EuGa2S4 compound.