AVS 46th International Symposium
    Flat Panel Displays Topical Conference Monday Sessions
       Session FP-MoA

Paper FP-MoA4
Blue Luminescence Properties of Zinc Oxide Doped with Low Concentration of Tungsten

Monday, October 25, 1999, 3:00 pm, Room 604

Session: Luminescent Thin Films
Presenter: J.B. Sobti, Texas A&M University
Authors: J.B. Sobti, Texas A&M University
V. Bhatia, Texas A&M University
P.M. Babuchna, Texas A&M University
M.H. Weichold, Texas A&M University
Correspondent: Click to Email
Research in developing high quality thin film phosphors for field-emission displays (FEDs) has gained momentum over the last decade. From the aspect of low voltage applications, cost and durability, efficient red and gren phosphors are now available. However, phosphors for blue light still need improvement. An investigation conducted at Texas A&M University showed that tungsten doped zinc oxide (ZnO:W) emits blue light at 490 nm when excited at 300V.@footnote 1@ Results for this phosphor preparation, its luminescence and material characterizations, and potential use in fabricating a FED are prsented in this paper. Using ion mill, thin films of ZnO and W were co-deposited. The films with varying W concentrations (10%, 30%, and 50%) were annealed at 450°C, 650°C, and 850°C for 4, 8, and 12hrs in the presence of argon and oxygen. Luminescent characterization of these films indicated that phosphor having 10% W, annealed at 850°C for 12 hrs. in pure argon emitted the brightest blue light.@footnote 2@ Continuing research involves studying the effect of even lower W concentrations under above-mentioned conditions. Radiance data for ZnO:W phosphor will be measured and compared with the efficiencies of other blue phosphors. X-ray diffraction studies and infrared spectroscopy of the films showed formation of zinc tungstate (ZnWO@sub 4@), which has been reported to exhibit photoluminescence at 490 nm. This led us to conclude that ZnWO@sub 4@ is the source of blue light from our phosphor.@footnote 3@ This paper also presents results from Stokes shift measurements to understand mechanisms for blue light emission. Research is underway in determining a material chemically compatible with the phosphor to form anode lines for the display. Results from this research will also be reported. @FootnoteText@ @footnote1@Technology Disclosure to TAMU Technical Licensing Office (1993). @footnote 2@J. B. Sobti et al, April 1998, AVS Texas Chapter meeting. @footnote 3@J. B. Sobti et al, Spring, 1999, MRS meeting.