Preparation of blue-emitting SrGa2Se4:Ce thin films by multi-source deposition

IIaIIIb2VIb4 ternary compound thin film doped with Ce3+ ion is of interest for full color thin-film EL display, because it shows blue emission with good chromaticity. In this investigation, SrGa2Se4:Ce thin films were prepared by the multi-source deposition technique using Sr, Ga2Se3, Se and CeF3 sources. Structural property and composition of the films deposited were characterized and the growth mechanism of the film was discussed. The SrGa2Se4 film could be successfully deposited without SrSe and GaSe phases at aGa2/Se3Sr flux ratio of 56 and at a substrate temperature of 450°C. It was shown that when Ga2Se3 evaporates from the source, it decomposes into GaSe and Se2. It is suggested from these results that the formation of SrGa2Se4 or SrSe depends strongly on the substrate temperature.