TAILIEUCHUNG - Báo cáo "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 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. | VNU Journal of Science Mathematics - Physics 24 2008 181-187 The role of color luminescence centers Mn Cu Co in the semicondutors with wide band gap ZnS ZnO and their applications Pham Van Ben Phan Trong Tue Department of Physics College of Science VNU 334 Nguyen Trai Thanh Xuan Hanoi Vietnam Received 22 May 2008 received in revised form 15 December 2008 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 ms ms and 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. Keywords ZnS ZnO photoluminescence PL time-resolved PL spectra. 1. Introduction ZnS ZnO are semiconductors with wide band gap Eg eV and eV for ZnS ZnO at respectively . These materials were applied widely in the field of electroluminescence displays such as luminescence diodes cathode ray tube transparent windows. 1-4 In visible region the photoluminescence PL spectra of ZnS materials include two wide luminescence bands at around 460 nm blue band and 515 nm green band . These bands are characterized by the vacancies of Zn bonding to Cl VZn-Cl and some impurities in ZnS crystal 5 . PL spectra of ZnO include luminescence bands at around 380 - 410 nm 500 - 530 nm and 590 - 620 nm. These bands are characterized by the .

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