Fabrication of thin-film cold cathodes by a modified chemical vapor deposition diamond process

Thin-film cold cathodes have been grown on molybdenum by a modified microwave assisted plasma chemical vapor deposition diamond process. Electron field-emission tests have been performed on the devices. The modification from the chemical vapor deposition diamond process includes the addition of N₂ and O₂ into the plasma during the growth stage. Characterization of these films indicates a disordered tetrahedral carbon structure. Raman spectroscopy shows a disturbance in the cubic symmetry of the lattice and x-ray diffraction indicates a disordered tetrahedral structure. Electron emission testing indicate low turn-on voltages. Current densities from 1 to 8 mA/cm² can be obtained for applied fields of 5–8 V/μm. The results are explained in terms of a change in the electronic band structure and the formation of states in the band gap. © 1998 American Vacuum Society.