Plasma enhancement of current from carbon cathodes for field emission displays

Summary form only given. In this paper, we examine the possibility of using a background gas medium to enhance the current available from low threshold carbon cathodes. The field emission current is used to initiate a plasma in the gas medium, and thereby achieve a current multiplication effect. Results on the variation of anode current as a function of electric field and gas pressure are presented. These are compared with model calculations to verify the principles of operation. The influence of ion bombardment on the long term performance thin film carbon cathodes is examined for He and Ar multiplication plasmas. A measure of the influence of current multiplication on display quality is presented by examining light output from two standard low voltage phosphors. Also studied are the influence of doping the carbon with N to lower the threshold voltage for emission as well as the consequent impact on anode current from the plasma. In addition, microscopic surface roughness of the cathode and its impact on emission properties are examined. The results presented will provide an evaluation of a combined field emission-plasma switching approach to obtain flat panel displays with increased brightness, viewing angle and wider range of operation temperature.