Effect of temperature on the degradation of ZnS FED phosphors

• Published in: Surface and interface analysis 2001-08, Vol.32 (1), p.110-113
• Main Authors: Swart, H. C., Hillie, K. T., Greeff, A. P.
• Format: Article
• Language: English
• Subjects: AES; Applied sciences; cathodoluminescence; cathodoluminescence, AES; Cathodoluminescence, ionoluminescence; Condensed matter: electronic structure, electrical, magnetic, and optical properties; degradation; degradation, phosphors; Display; Electronics; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other luminescence and radiative recombination; phosphors; Physics; temperature
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/sia.1018

The changes in cathodoluminescent brightness and changes in the surface chemistry of ZnS:Cu,Al,Au have been investigated using Auger electron spectroscopy (AES) and a photospectrometer. The ZnS:Cu,Al,Au phosphor powders have been subjected to electron beam bombardment of 2 keV, with an electron beam current density of 88 mA cm−2 at an oxygen pressure of 2 × 10−6 Torr. The studies were carried out between room temperature and 310 °C. Degradation was manifested by a non‐luminescent ZnO layer that formed on the surface of the phosphor according to the electron‐stimulated surface chemical reaction (ESSCR) mechanism. An increase in temperature led to a decrease in the surface reaction rate due to a decrease in the mean surface lifetime of the oxygen molecules on the surface, with a direct decrease in the ESSCR probability. Without the presence of the electron beam, no chemical reactions occurred on the surface up to 310 °C. Local heating due to the electron beam irradiation is not responsible for the chemical reactions on the ZnS phosphor surface. Copyright © 2001 John Wiley & Sons, Ltd.