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A comparison of the degradation mechanisms in ZnS and Y 2 O 2 S:Eu powder FED phosphors
Author(s) -
Trottier T. A.,
Swart H. C.,
Jones S. L.,
Sebastian J. S.,
Holloway P. H.
Publication year - 1996
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1889/1.4731191
Subject(s) - phosphor , cathodoluminescence , auger electron spectroscopy , analytical chemistry (journal) , impurity , materials science , scanning electron microscope , degradation (telecommunications) , nuclear chemistry , chemistry , luminescence , physics , optoelectronics , organic chemistry , chromatography , computer science , nuclear physics , composite material , telecommunications
— The degradation of Y 2 O 2 S:Eu phosphor powders was studied using Auger electron spectroscopy (AES) and cathodoluminescence (CL). The phosphors were exposed to electron bombardment (2 keV, 2 mA/cm 2 ) at residual background gas pressures from 2 × 10 −8 to 10 × 10 −8 Torr. The results indicate that the degradation is due to electron‐stimulated surface reactions caused by electron‐beam dissociation of molecular species at the phosphor surface. AES data show that the surface was initially contaminated by C‐containing impurities, and that both C and S were depleted during electron bombardment. Increased rates of depletion of C and S were observed for higher pressures, suggesting that the concentration of molecular species on the phosphor surface was limiting the rate of reaction and removal of C and S. Quantification of the AES results and inspection of CL spectrum suggest that the surface was converted to a non‐activated Y 2 O 3 . Comparison of the degradation of Y 2 O 2 S:Eu and ZnS: X ( X = Ag, Cl or X = Al, Au, Cu) showed that ZnS phosphors were more susceptible to degradation caused by surface changes induced by electron‐beam bombardment. The degradation rate of the ZnS phosphors was approximately 3 times faster than the Y 2 O 2 S:Eu.