Electron emission amplification of cold cathode by two-layer diamond coating

Abstract

The results of experimental investigations of electron emission of molybdenum cathodes with two-layer diamond films are presented. For two-layer coating, the first layer of the two was a high-conductivity nanocrystalline diamond film heavily doped with nitrogen, and the second layer was a thin microcrystalline high-quality diamond film. The emission characteristics of the cathodes were determined on the basis on analyzing the output parameters of a high-power rf pulse compressor, in which these cathodes were used in the high-current (>100 A) regime. In the experiment, the current increasing for the cathode with twolayer coating in comparison with cathodes without and with one layer was observed. This effect of the current increasing can be explained by amplification of the electron beam in the process of the secondary electron emission as the beam passes through the second diamond film.