AVS 47th International Symposium
    Flat Panel Displays Tuesday Sessions
       Session FP-TuM

Paper FP-TuM11
Temperature Dependence of Cathodoluminescent Degradation of ZnS Phosphor

Tuesday, October 3, 2000, 11:40 am, Room 313

Session: Luminescent Materials
Presenter: B. Abrams, University of Florida
Authors: B. Abrams, University of Florida
W. Roos, University of the Orange Free State
L.C. Williams, University of Florida
P.H. Holloway, University of Florida
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The effect of temperature on ZnS:Ag,Cl cathodoluminescent (CL) intensity and degradation by surface chemistry changes has been investigated using an Oriel optical spectrometer and a scanning Auger electron spectrometer. With vacuum pressures maintained between 3-5x10@super-9@ Torr, thermal quenching has been measured on the ZnS:Ag,Cl powder pressed into an Al cup and mounted onto a heater stage. Using a 2kV accelerating voltage, a constant current of 5µA and a 1mm spot size, the sample temperature was incrementally increased to 400@supero@C with CL and AES measurements being taken after each increase. AES data show little change in the S, Zn, O and C peaks on the surface as the temperature is increased. There is also no significant shift in Auger peak energies with temperature. The CL brightness decreased dramatically at T@>=@300@supero@C, while the maximum CL peak intensity shifted from 450nm to almost 600nm. CL brightness measurements taken as the sample was incrementally cooled back towards room temperature showed that the most intense CL peak shifted back to 450nm. However, a large hysteresis was observed in the CL intensity versus temperature data due to poor heat transfer. Recovery of the CL intensity upon returning to RT ranged from 70% recovery to 100% recovery dependent upon the hold time at each temperature. The mechanisms for these effects will be discussed. This work was supported by DARPA Grant MDA 972-93-1-0030 through the Phosphor Technology Center of Excellence.