The role of color luminescence centers Mn, Cu, Co in the semicondutors with wide band gap ZnS, ZnO and their applications

Abstract

In this paper, materials of ZnS:Cu, ZnS:Mn and ZnO:Co were prepared by ceramic method and co-precipitated method. The presence of transition metals such as Cu2+(3d9), Mn2+(3d5) in ZnS and Co2+(3d7) in ZnO make blue bands at around 476 nm, 486 nm and green band at around 514 nm disappeared. Simultaneously, there are luminescence bands at around 533 nm, 582 nm, 693 nm for bulk samples of ZnS:Cu, ZnS:Mn, ZnO:Co and 603 nm for nanocrystalline sample of ZnS:Mn. These bands are characterized by Cu2+ ions, Mn2+ ions: [4T1-6A1] and Co2+ ions: [4T1-4A2] in ZnS:Cu, ZnS:Mn and ZnO:Co, respectively. Time-resolved luminescence spectra of these samples show that lifetime of electrons at excited states is 1.90 ms, 0.79 ms and 8.60μs corresponding to bulk sample ZnS:Mn, nanocrystalline sample ZnS:Mn and bulk sample ZnS:Cu. The luminescence material of ZnS:Cu has been tested in off-set print for anti-imitated stamps.