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 e mploying simultaneous evaporation of gallium sulfide (Ga2S3) and ceriu m-activated strontium sulfide (SrS). The growth kinetics of SrGa2S4 wa s studied by investigating the crystallographic structure and composit ion of evaporated films as a function of the substrate temperature and impingement flux ratio with the aid of energy-dispersive x-ray microa nalysis and x-ray diffraction measurements. With regard to uniform cry stalline structure and stoichiometric compositiion, a Ca2S3/SrS flux r atio in the 60 to 100 range was empirically found to give the best res ults for a substrate temperature of 460 degrees C. The Ce-doped SrGa2S 4 films exhibit the characteristic photoluminescent emission which is dominated by the D-2-F-2(5/2) transition within the Ce3+ ions occurrin g at 445 nm in the blue region.