High-Density Electron Emission From Ion-Implanted Diamond

We report high-density electron emission characteristics from ion-implanted homo-epitaxial diamond. At the previous this conference, we had reported over 100mA/sq cm electron emission from a sulfur-ion implanted homo-epitaxial diamond. To find best ion-species and implant-conditions, three types of ions such as phosphor, boron and sulfur have been implanted and their characteristics were evaluated. Among the above species, the phosphor-ion implanted sample showed highest electron emission density over 1A/sq cm with emission area of 300, microns in diameter. We believe that this is one of the largest emission density values for carbon-based materials under a large emission area measurement. From the measurement of electron emission, maximum emission densities of individual samples were found to exclusively obey to their surface conductivity rather than the implanted ion-species. Also, a graphitized defect was observed at the surfaces of well emitting samples. These results and emission characteristics indicated that high-density electron emission is strongly related to the conductive carbon structure together with the semiconducting diamond matrix. Detailed emission characteristics and emission models will be discussed.