Electron emission characteristics of polycrystalline diamond films

Electron emission characteristics have been investigated for polycrystalline diamond films subjected to H2 plasma treatment, O2 plasma treatment, and annealing. In the case of surface treatments of diamond film, the voltage commencing electron emission increases due to O2 plasma treatment or annealing and is recovered by the subsequent H2 plasma treatment. On the other hand, in the case when the rear face of the diamond film is treated with O2 plasma or annealed in diamond/Au samples, no recovery of the voltage occurs due to H2 plasma treatment after O2 plasma treatment or annealing. 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.