DEGRADATION BEHAVIOR OF ZNS PHOSPHOR POWDERS UNDER DIFFERENT EXPERIMENTAL CONDITIONS

The phosphor powder ZnS:Cu,Al,Au has been investigated extensively as a possible green phosphor for field emission displays (FEDs). Phosphor powders of ZnS:Cu,Al,Au have been subjected to electron bombardment ( 1-5 keV) at oxygen pressures ranging from 1 x 10(-7) to 2 x 10(-6) Tor r and different electron current densities (45-58 mA cm(-2)). Auger el ectron spectroscopy (AES) and cathodoluminescence (CL), both excited b y the same electron beam, were used to monitor changes in surface comp osition and luminous efficiency during electron bombardment. It was sh own that the degradation rate of the CL intensity is a linear function of oxygen pressure. The interactive constant (a measure of the probab ility of surface reactions) and the burning parameter (a measure of th e probability of CL degradation per incident electron) plotted as a fu nction of electron beam energy follow the same trend as the electron i mpact ionization cross-section for an atom. (C) 1998 John Wiley & Sons , Ltd.