CVD DIAMOND COATINGS FOR A TAILORED WORK FUNCTION COLD CATHODE

BECAUSE OF THEIR UNIQUE ELECTRONIC PROPERTIES, DIAMOND THIN FILMS OFFER AN OPPORTUNITY TO GREATLY IMPROVE THE EFFICIENCY OF MICROWAVE POWER TUBE SYSTEMS BY USING A HIGH EFFICIENCY COLD CATHODE EMPLOYING DIAMOND NEGATIVE ELECTRON AFFINITY COATINGS TO ACHIEVE LOW WORK FUNCTION AND LOW EMITTER RESISTANCE^ IN ADDITION, BECAUSE OF DIAMOND'S THERMAL SHOCK RESISTANCE AND RESISTANCE TO RADIATION AND CHEMICAL ATTACK, DIAMOND COATED CATHODES MAY ALSO IMPROVE THE LIFE AND RELIABILITY OF THE POWER TUBE SYSTEMS. THIS PROPOSAL IS INTENDED TO EXPLORE THE FEASIBILITY OF DIAMOND-COATED CATHODES AND TO DETERMINE THE OPERATIONAL ADVANTAGES OF SUCH SYSTEMS IN POTENTIAL FIELD APPLICATIONS. NITROGEN AND PHOSPHORUS DOPED DIAMOND THIN FILMS WILL BE GROWN AND CHARACTERIZED PHYSICALLY AND ELECTRONICALLY. VACUUM DIODES WILL BE FABRICATED AND THE CURRENT-VOLTAGE CHARACTERISTICS MEASURED AS A FUNCTION OF CATHODE TEMPERATURE AND FIELD TO DETERMINE WORK FUNCTION AND RESISTANCE, ESTABLISHING THE FEASIBILITY OF THIS APPROACH TO IMPROVING CATHODES. PHASE II WILL FOCUS ON FABRICATING AND CHARACTERIZING DIAMOND CATHODE COMPONENTS FOR USE IN EXISTING OPERATIONAL SYSTEMS.