Effect of Oxygen Pressure During Zno:Al Coating of Zns:Ag Phosphor on Cathodoluminescent Degradation Lifetime
- PDF / 284,638 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 99 Downloads / 171 Views
Y4.3.1
EFFECT OF OXYGEN PRESSURE DURING ZnO:Al COATING OF ZnS:Ag PHOSPHOR ON CATHODOLUMINESCENT DEGRADATION LIFETIME
M. Ollinger, V. Craciun, S. Nagore, and R.K. Singh Materials Science and Engineering, University of Florida, Gainesville, FL 32601
ABSTRACT The reduction in cathodoluminescent (CL) degradation of ZnS:Ag phosphor particles coated with aluminum doped zinc oxide (ZAO) films has been investigated. The films were deposited under various oxygen pressures using the atomic flux coating process. The characteristics of the coated phosphor particles with respect to as-received ones were investigated by x-ray photoelectron spectroscopy, CL degradation and scanning electron microscopy. All coated phosphor particles exhibited less CL degradation than the uncoated particles. The coatings deposited under 1.6x10-4 Torr of oxygen, a pressure much lower than the optimum one required to obtain highly transparent and conductive ZnO:Al films, provided the longest brightness lifetime. This increased phosphors lifetime was attributed to the high reactivity of the oxygen deficient ZAO coatings which acted as a sacrificial layer and trapped reactive species before they can reach the phosphor particles and alter their chemical composition.
INTRODUCTION For many years the display industry has attempted to create a thin, flat, low power version of the highly successful cathode ray tube. While efforts have led to a number of flat panel display (FPD) technologies, not one has yet met all of the needs for reduced power consumption, brightness efficiency, video response, viewing angle, operating temperature, full color gamut and scalability [1]. Field emission display (FED) technology could meet all these requirements, but its reliability has been plagued by technological shortcomings. For example, the use of sulfide-based phosphors in FEDs has resulted in a rapid decay of screen brightness during continuous electron beam bombardment. Proposed mechanisms for the loss of brightness, or cathodoluminescent (CL) degradation of sulfide-based phosphors, have included electron stimulated surface chemical reactions (ESSCR) [2-4], accumulation of graphitic carbon [5], charging effects [4, 6], and point defects injunction [4, 6, 7]. A general solution to prevent the CL degradation is to coat the phosphor powders with a transparent and conductive oxide (TCO) film. By using the atomic flux coating process (AFCP) we showed that ZnS:Ag particles coated with nanometer-thick indium tin oxide films exhibited a significantly slower CL degradation than uncoated particles [8]. Recently, aluminum doped ZnO (ZAO) films have attracted interest as TCOs because the material is inexpensive, abundant and has a low growth temperature and high stability in hydrogen plasma [9]. In
Downloaded from https://www.cambridge.org/core. Access paid by the UCSF Library, on 05 Oct 2019 at 19:10:29, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/PROC-780-Y4.3
Y4.3.2
addition, by changing the oxyg
Data Loading...
