Field emission measurements from carbon films of a predominant nano-crystalline diamond character grown by energetic species

• Published in: Diamond and related materials 2006-04, Vol.15 (4), p.846-849
• Main Authors: Shpilman, Z., Michaelson, Sh, Kalish, R., Hoffman, A.
• Format: Article
• Language: English
• Subjects: Carbon nano-grained films; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Diamond properties and applications; Electron and ion emission by liquids and solids; impact phenomena; Electron energy loss spectra; Electron field emission (EFE); Exact sciences and technology; Field emission, ionization, evaporation, and desorption; Impact phenomena (including electron spectra and sputtering); Ion and electron beam-assisted deposition; ion plating; Low turn on field (TOF); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2005.10.060

Here we report for the first time on the electron field emission (EFE) properties of carbon films of a predominant nano-crystalline diamond character deposited by the glow discharge direct current (GDDC) technique in our laboratory. By this method, film growth occurs by a subsurface implantation process of energetic carbon species without any pretreatment. These Nano-diamond (ND) films comprise an amorphous layer a few nanometer thick on their surface. The presence of this surface layer inhibits EFE of the as-deposited films, which only comes to electrical discharge (ED). After removal of the amorphous layer by short hydrogen plasma etch (leaving the layer to be H-terminated ND), the film emits at a turn on field (TOF) of 15.4 ± 2 and 14 ± 3 V/μm for different samples. Thermal treatment of this film at 1030 °C removes the hydrogen from the surface layer and results in surface reconstruction creating a partially graphitic surface, which leads to degraded EFE properties. Surface composition, structure and morphology of the films are correlated to the EFE properties by using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS).