Electron emission characteristics of polycrystalline diamond films

Electron emission characteristics have been investigated for polycrystalline diamond films. O-2 plasma treatment or annealing of the diamond surface leads to an increase of the electric field commencing electron emission in comparison with that for H-2 plasma treated one. Emission characteristics are recovered by H-2 plasma treatment after O-2 plasma treatment or annealing. An increase of the electric field also occurs for diamond /Au samples in which the rear face of the diamond film is treated with O-2 plasma or annealed. However, MO recovery of the electric field occurs even though H-2 plasma treatment is carried out at the rear face after O-2 plasma treatment or annealing. It is demonstrated 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.