Abstract
Alkali metal doped SrS:Ce,M (M=Na, K, or Rb) thin film EL devices have been prepared by electron-beam evaporation. Alkali metal doping causes suppression of formation of Sr vacancies, and results in decrease of Ce^<3+>-V_<Sr> complex center formation. Among those dopants, Rb is the most effective. The SrS:Ce,Rb phosphor powder prepared with Ce concentration of 1.0 mol% shows the strongest photoluminescence with the bluish-green luminescence due to isolated Ce^<3+> centers.