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

Paper FP-TuM5
Energy Loss Mechanisms in Pulsed Laser Coated Cathodoluminescent Phosphors

Tuesday, October 3, 2000, 9:40 am, Room 313

Session: Luminescent Materials
Presenter: W.J. Thomes, University of Florida
Authors: W.J. Thomes, University of Florida
P.H. Holloway, University of Florida
C.H. Seager, Sandia National Laboratories
D.R. Tallant, Sandia National Laboratories
Correspondent: Click to Email
Coatings of MgO and Al@sub 2@O@sub 3@ were pulsed laser deposited onto sedimented screens of Y@sub2@O@sub 3@:Eu and Y@sub 2@SiO@sub 5@:Tb to study energy loss mechanisms in the coatings and to predict their impact on cathodoluminescence (CL). The thickness of the pulsed laser deposited coatings, characterized by ellipsometry, TEM and AES sputter profiles, were varied from 75 to 500 Angstroms by changing the deposition time and oxygen background pressure. A Si shadow mask covered half of the sedimented powder during deposition to allow comparison of coated and uncoated powder. DC and pulsed cathodoluminescence data were collected using an Ocean Optics fiber optic spectrometer or a modified Kimball Physics electron gun, respectively. Light was collected using fiber optics connected to a photomultiplier tube or a CCD detector. The beam energies were varied from 0.8 to 4 keV, while the current was kept constant at 0.16 µA/cm@super 2@. The coating thickness on particles was modeled by assuming a uniform flux depositing over a spherical powder surface. Spatially resolved electron energy loss was calculated to predict the CL intensity versus beam energy and incident angle relative to the local surface normal. The predictions of the CL intensity versus incidence angle, coating thickness, and primary beam energy agreed well with experimental data. The consequences of these data relative to phosphor degradation and low voltage efficiency will be discussed.