Electron emitter device of NEA diamond thin film

A new type of cold cathode of chemical vapor deposited diamond thin film is proposed. The electron emitter consists of a hydrogenated diamond surface of negative electron affinity (NEA) which also is a p-type semiconducting layer, and a metal-insulator-semiconductor (MIS) structure for electron injection into the diamond film. The diamond film is deposited by microwave plasma chemical vapor deposition (CVD) and thinned by electron cyclotron resonance (ECR) plasma etching. The p-type conductivity of the hydrogenated diamond surface is taken into consideration as well as the NEA feature itself to design the emitter device. The emitter worked from a low driving voltage of 40 V with high cathode efficiency of 2%, which mean the applying voltage for the MIS diode and the ratio of the emission current to the diode current, respectively. The emission current of 20 pA was obtained at a driving voltage of 100 V for the fabricated cathode.