Fabrication and Field Emission Properties of Diamond-Like Carbon Nanostructure Arrays Deposited by Filtered Cathodic Vacuum Arc

Abstract

Diamond‐like carbon (DLC) films are deposited by filtered cathodic vacuum arc (FCVA) at room temperature. Well‐aligned DLC nanofiber arrays are structured using porous anodic aluminum oxide (AAO) templates. Along with a slow process of template etching, the DLC nanofibers gradually bend over and closely weave into a mask, preventing the AAO from entirely dissolving into the etching solution. This resist‐mask of DLC/AAO nanostructure is removed by the effect of electric charge accumulation at a high electric field and then the DLC nano‐whisker array is formed. The electron field emission (EFE) properties of DLC nanoarrays indicate a low turn‐on field of 1.60 V µm−1 and a threshold field of 2.98 V µm−1. These DLC nanowhisker arrays signify a high potential for assembling carbon‐based vacuum microelectronic devices.

Dependence of Optimum Thickness of Ultrathin Diamond-like Carbon Coatings over Carbon Nanotubes on Geometric Field Enhancement Factor

“…For both sets, the turn-on fields of DLC-coated CNTs are higher than those of pristine CNTs, which could be attributed to the chemical bond component of FCVA-DLC coatings. Owing to the fact that the DLC films coated by FCVA evaporation with a rather low deposition rate have a high sp 3 bonding content (>80%), as demonstrated by our previous work, the conductivity, σ, of low deposition rate FCVA-DLC coatings is accordingly lower than that of DLC films deposited by other methods (e.g., ∼40%). Since low conductivity of DLC coatings impedes the FE properties, the turn-on field, E 0 , of such FCVA-DLC-coated CNTs increases as compared to that of pristine CNTs.…”

“…Finally, ultrathin DLC coating materials were directly deposited on the CNT arrays by the FCVA technique at room temperature, as indicated in Figure c. The bias voltage of Si/CNT substrates was −50 VDC, by which the kinetic energy of the impinging carbon ions was estimated to be around 100 eV so as to contribute to a high sp 3 bond content . The upper-left inset of Figure shows a top-view SEM micrograph of the CNT/DLC emitter array at low magnification.…”

“…The bias voltage of Si/CNT substrates was −50 VDC, by which the kinetic energy of the impinging carbon ions was estimated to be around 100 eV so as to contribute to a high sp 3 bond content. 43 The upper-left inset of Figure 1 shows a top-view SEM micrograph of the CNT/DLC emitter array at low magnification. The microstructures of CNT/DLC composite emitters, as revealed by SEM and TEM, are shown in Figure 2.…”

“…Attributed to the absence of hydrogen, the thermal and illuminated instabilities of hydrogenated amorphous carbon (a-C:H) 38,42 films have been avoided. We demonstrated in our previous work 43 that ultrathin DLC films and DLC nanostructures with a high sp 3 -bonded content, which had exhibited excellent FE properties, could be realized by the FCVA technique. Besides being of high quality, the DLC films were deposited at room temperature, and the energy of carbon ions impinging the growth surfaces was dozens of electronvolts, which provided an optimized sp 3 bonding percentage.…”