連続蒸着法によるZnS (Cu, Mn)薄膜の作製条件と直流EL

抄録

To improve the characteristics of a DC thin film EL device, it is required to make a high crystalline phosphor film. In this paper, by using a successive vaccum deposition method, the fabrication conditions of the ZnS (Cu, Mn) thin film which has a high crystallinity are investigated. The ZnS (Cu, Mn) film is made by successively depositing ZnS (1), Mn, Cu and ZnS (2) on a glass substrate which was coated with SnO₂ electrode. The diffusion of Mn, Cu into the host ZnS is carried out by increasing the substrate temperature to 580°C during deposition of the ZnS (2) film. In order to grow the ZnS (2) film on the ZnS (1) film epitaxially, a highly oriented ZnS film as the ZnS (1) film is used. After diffusing most of Mn, Cu into the ZnS (1) film, the ZnS (2) film is deposited. It is found that the ZnS (1) film deposited under keeping the substrate at 300°C has best crystal orientation along <111> direction. Therefore, the ZnS (2) film grown along its direction is made and the highly oriented ZnS (Cu, Mn) film is obtained. With this ZnS (Cu, Mn) film, we have succeded in fabricating the DC thin film EL device which has a luminous efficiency of 0.92 lm/W at the luminance of 1, 300 cd/m² and which can continuously drive a luminance of 330 cd/m² for 1, 100 hours (half-life of 3, 400 hours).