Characteristics of metal-polycrystalline diamond contact field emitters

Electron emission characteristics have been investigated for polycrystalline diamond films. When the surface of the diamond films deposited on Si substrates and the rear face on which Au/diamond contact is formed are subjected to O₂ plasma treatment or annealing, an increase of the electric field commencing electron emission occurs in comparison with that for H₂ plasma-treated diamond surface. In the case of the surface treatment, emission characteristics are recovered by H₂ plasma treatment after O₂ plasma treatment or annealing, while no recovery of the electric field occurs for the Au/diamond sample in which the rear face of the diamond film is treated in the same manner. It is suggested that there exists another factor dominating the field emission characteristic other than field emission mechanisms such as electron injection at the diamond-metal contact and electron emission at the surface with negative electron affinity.