Enhanced luminescence in ZnGa2O4-xSx:Mn2+ thin-film phosphors grown on MgO(100) substrate

Mn-doped ZnGa2O4-xSx thin-film phosphors have been grown using a pulsed laser deposition technique at varying growth conditions. Structural characterization was carried out on a series of ZnGa2O4-xSx:Mn2+ films grown on MgO(100) substrates using Zn-rich ceramic targets. Oxygen pressure was fixed at 100 mTorr and substrate temperatures were varied from 500 to 700 °C. The results of X-ray-diffraction patterns showed that the lattice constants of the ZnGa2O3.95S0.05:Mn2+ thin films decrease with the substitution of sulfur for the oxygen in ZnGa2O4. Measurements of photoluminescence (PL) properties of ZnGa2O4-xSx:Mn2+ thin films have indicated that MgO(100) is one of the most promising substrates for the growth of high-quality ZnGa2O4-xSx:Mn2+ thin films. In particular, the incorporation of sulfur into the ZnGa2O4 lattice could induce a remarkable increase of PL. The highest green-emission intensity was observed with ZnGa2O3.95S0.05:Mn2+ films, whose brightness was increased by a factor of 3.5 in comparison with that of ZnGa2O4:Mn2+ films. This phosphor may be promising for application to flat-panel displays.