For the improvement of emission efficiency, ZnS-doped Mg0.8Ca0.2S:Eu phosphor film was made using rf-magnetron sputtering method. When the concentration of ZnS in the film is 4%, the photoluminescence intensity is about three times higher than that of ZnS-non-doped Mg0.8Ca0.2S:Eu film with keeping pure red emission (similar to 650 nm). The crystal planes are oriented in (200) direction and make a solid solution with ZnS. Enhancement in photoluminescence (PL) intensity is closely related to the change of the crystal quality. (c) 2004 Elsevier B.V. All rights reserved.