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In this study, the mixtures of ZnO and Ga2O3 powder with addition of LiCl flux were fired, the raw material mixing ratio, doped with Mn 2+ and firing atmosphere effects on phosphor characteristics were investigated. When fired at 1200°C, its phosphor powder emits a broad-band spectrum range between 375 nm to 700 nm, with a peak at 470 nm. | JOURNAL OF MATERIALS SCIENCE MATERIALS IN ELECTRONICS 9 1998 283-288 A study of ZnGa2O4 phosphor prepared by the solid method KAI-HUNG HSU MU-RONG YANG KO-SHAO CHEN Department of Materials Engineering Tatung Institute of Technology Taipei 104 Taiwan In this study the mixtures of ZnO and Ga2O3 powder with addition of LiCl flux were fired the raw material mixing ratio doping with Mn2 and firing atmosphere effects on phosphor characteristics were investigated. When fired at 1200 C its phosphor powder emits a broad-band spectrum range between 375nm to 700 nm with a peakat 470nm. The optimal composition of phosphors is about ZnO Ga2O5 47 53. Manganese-doped ZnGa2O4 fired in air exhibits two new emission bands with peaks at 506nm Mn2 emission centre and 666nm Mn4 emission centre . However if fired under vacuum the emission spectrum presents only the 506 nm peak with increased intensity. The 666 nm emission peak derived from a little Mn2 oxidized to Mn4 which substituted Ga3 to occupy the B sites of the spinel structure. The emission intensity of the 506nm peak of Zn1 XMnxGa2O4 is strongest when Mn2 x 0.006 and decreases markedly as the concentration of Mn2 exceeds x 0.01. Most of the substitutional Mn2 doping species in spinel ZnGa2O4 occupy the zinc sites. The luminescent band was associated to the spin-forbidden transition 4Ti 4G P 6Ai 6S . 1998 KluwerAcademic Publishers 1. Introduction In recent years more efficient cathodoluminescent phosphors are being widely investigated for applications in monitors high dehnition television HDTV and vacuum fluorescent displays VFDs 1 2 . However VFDs are operated by only 30 V d.c. or less when they are used as indicators on aircraft control panels or automobile dashboards 2 . Therefore a range of new phosphors such as ZnGa2O4 for operating at low voltages are being developed. ZnGa2O4 is a self-activated phosphor which emits blue light under excitation by both ultraviolet light and low voltage electrons 30 V d.c. . Excellent .
