Abstract
SrGa_2S_4 : Ce films for blue-emitting thin-film electroluminescent devices have been prepared by multi-source deposition. Sr, Ga_2S_3 and CeCl_3 were used as source materials. It was found that Ga_2S_3 was decomposed to GaS and S_2 at the evaporation source, then GaS and S_2 vapors arrived at the substrate. The formation of SrGa_2S_4,GaS and SrS depends on the substrate temperature and Ga_2S_3/Sr flux ratio. It was also found that the annealing in H_2S atmosphere was considerably effective for the improvement of the crystallinity and PL intensity of the SrGa_2S_4 : Ce thin films. The SrGa_2S_4 : Ce film that was deposited at a Ts=450℃ and flux ratio of 100,and annealed at 800℃ for 3 hours in H_2S showed strong blue PL with CIE coordinate of (0.12,0.09).
