Field emission from tetrahedral amorphous carbon

Field emission has been measured from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum arc. The threshold field and current densities achievable have been studied as a function of their ${\mathrm{sp}}^3$ content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold field of 10–20 V/μm, decreasing with increasing ${\mathrm{sp}}^3$ content, and optimally nitrogen doped films exhibit threshold fields as low as 3–5 V/μm.