Structural and photoluminescent properties of S-doped ZnGa2O4:Mn2+ thin-film phosphors grown on various substrates by pulsed laser deposition

S-doped ZnGa2O4:Mn2+ thin-film phosphors have been grown on Si (100), Al2O3 (0001), and MgO (100) substrates by using the pulsed laser deposition technique. The structural characterization and luminescent properties of S-doped ZnGa2O4:Mn2+ films, according to oxygen pressures, were investigated. The films grown on substrates have different crystallinity and surface morphology. The photoluminescence (PL) of the films is highly dependent on the deposition conditions and, in particular, the oxygen pressure and the type of substrate. The highest emission intensity was observed with S-doped ZnGa2O4:Mn2+ films grown on MgO (100) substrates, whose brightness was 2.7 and 5.8 times higher than those of the films grown on Al2O3 (0001) and Si (100) substrates, respectively. It is indicated that MgO (100) substrate supports epitaxial growth of S-doped ZnGa2O4:Mn2+ films and larger grain size, due to high crystallinity, than any other substrates.