The changes in cathodoluminescent brightness and changes in the surface che
mistry of ZnS:Cu,Al,Au have been investigated using Auger electron spectros
copy (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 x 10(-6) Torr.
The studies were carried out between room temperature and 310 degreesC. Deg
radation was manifested by a non-luminescent ZnO layer that formed on the s
urface of the phosphor according to the electron-stimulated surface chemica
l 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 ESSC
R probability. Without the presence of the electron beam, no chemical react
ions occurred on the surface up to 310 degreesC. Local heating due to the e
lectron beam irradiation is not responsible for the chemical reactions on t
he ZnS phosphor surface. Copyright (C) 2001 John Wiley & Sons, Ltd.