Optimum IV-group ion concentrations in ZnGa2O4−xMx (M=S, Se, Te) phosphors for enhancement of luminescence

The ZnGa2O4−xMx (M=S, Se, and Te ) samples with varying S, Se, and Te concentrations are synthesized through solid-state reactions. The X-ray diffraction patterns of ZnGa2O4−xMx (M=S, Se, and Te) show that the positions of the (4 0 0) diffraction peak gradually shift to lower angles due to the doping of VI-group ions (S, Se, and Te) with larger ionic radius than oxygen. For ZnGa2O4−xSx samples, the solubility limit is found to be about x=0.30. The cathodoluminescence measurements on ZnGa2O4−xMx samples show that the optimized S, Se, and Te concentrations with the highest cathodoluminescence intensities are 0.10, 0.05, and 0.03, respectively. The luminous intensity of ZnGa2O3.95Se0.05 is four times higher than that of ZnGa2O4. Thus, ZnGa2O3.95Se0.05 can be a promising candidate phosphor for FED applications.