Optical spectroscopy studies of surface breakdown of polycrystalline diamond thin films in vacuum

Diamond is known to be an excellent electrical insulator and thermal conductor. These properties of diamond make it an attractive candidate as the insulating material for high voltage systems to be used in low earth orbit (LEO) and interplanetary space environment. However, to the knowledge of the authors, the surface flashover and surface breakdown characteristics of polycrystalline diamond thin films have not been investigated to date. In this work we will present experimental results of surface flashover characteristics of polycrystalline diamond and other synthetic thin films in vacuum. Electrical characteristics of surface breakdown and optical emission spectra of the surface flashover plasma are investigated. Optical spectroscopic studies of the luminosity of the discharge reveals information about the excited and ionized species in the vicinity of the surface. An optical multi channel analyzer was used to identify the emission lines of the optical spectrum