CATHODOLUMINESCENT DISPLAY PHOSPHORS

摘要

The past several years rendered a resurgence of interest in phosphors for low-voltage flat panel displays utilizing cathodoluminescence (CL). A major selection criterion for these phosphors is CL efficiency. The objective is to maximize the efficiency at low voltages. This work focuses on understanding the materials properties that influence CL efficiency below 1 kV. Existing high-voltage CL efficiency models take into account intrinsic materials properties such as band-gap energy. Experimental data reveals that the CL efficiency also depends on physical properties such as particle and crystallite size. An updated, predictive model of CL efficiency that includes the effects of crystallite size, radiative recombination probability, and electron accelerating potential was developed. The predicted efficiencies agree very well with experimental results. The experimental data were collected using a hot filament electron gun in a demountable high-vacuum chamber. To obtain measurement accuracy, secondary electrons were collected and the phosphor excited with a uniform beam profile. A CL characterization protocol for display phosphors was established at Sandia National Laboratories and made available to phosphor researchers.