Growth and characterization of blue emitting phosphor films of SrGa2S4:Ce prepared by deposition from binary vapors

A deposition from binary vapors (DBV) has been developed into a novel technique for the growth of polycrystalline thin films of SrGa2S4 by employing simultaneous evaporation of gallium sulfide (Ga2S3) and cerium-activated strontium sulfide (SrS). The growth kinetics of SrGa2S4 was studied by investigating the crystallographic structure and composition of evaporated films as a function of the substrate temperature and impingement flux ratio with the aid of energy-dispersive x-ray microanalysis and x-ray diffraction measurements. With regard to uniform crystalline structure and stoichiometric compositiion, a Ca2S3/SrS flux ratio in the 60 to 100 range was empirically found to give the best results for a substrate temperature of 460 degrees C. The Ce-doped SrGa2S4 films exhibit the characteristic photoluminescent emission which is dominated by the D-2-F-2(5/2) transition within the Ce3+ ions occurring at 445 nm in the blue region.