The role of color luminescence centers Mn, Cu, Co in the semicondutors with wide band gap ZnS, ZnO and their applications
In this paper, materials of ZnS:Cu, ZnS:Mn and ZnO;Co were prepared by ceramic
method and co-precipitated method. The presence o f transition metals such as Cu^^(3d’), Mn^^(3d^) 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 o f ZnS:Cu, ZnS:Mn, ZnO;Co and 603 nm for nanocrystallme sample of ZnS:Mn. These bands are characterized by ions, ions: [4Ti-6Ai] and ions: [4T1-4Aa] in ZnS’.Cu, ZnS;Mn and ZnO:Co, respectively. Time-resolved luminescence spectta of these samples show that lifetime of eletrons at excited states is 1.90 ms,0.79 ms aiid 8.60 /JS 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.
