Effect of Ho^3＋ Ion on Luminescent Property of CaGaeS4：Eu^2＋

The afterglow luminescent property and thermo-luminescence (TL) of CaGa2S4：Eu^2 , Ho^3 were systemateally investigated. The afterglow of Eu and Ho Co-doped CaGa2S4 shows a broadband emission at 552 nm, which is the same as that of Eu doped CaGa2S4 only. And the decay behavior of CaGa2S4 Eu^2 , Ho^3 was investigated, which shows that CaGa2S4: Eu^2 , Ho^3 is a phosphor with long after-glow, whereas the CaGazS4:Eu^2 is a phosphor with-out long afterglow. Comparison of TL curves and 3D-TL emission spectra of CaGa2S4:Eu^2 ,Ho^3 and Ca-C, a2S4:Eu^2 show that a new trap center is produced at about 80℃, which is the basic reason of CaGazS4:Eu^2 ,Ho^3 with long afterglow.