Characterization of the Field Emission Properties of Carbon Nanotubes Formed on Silicon Carbide Substrates by Surface Decomposition

Dense arrays of vertically aligned carbon nanotubes CNTs form on the surface of silicon carbide wafers during high temperature anneals under moderate vacuum conditions. The novelty of this growth method is that the CNTs form without the aid of a metal catalyst, allowing for potentially impurity-free CNTs to form. In this study, CNT films were grown by the surface decomposition of silicon carbide substrates. The associated field emission characteristics were investigated to determine if films grown using this method possessed advantages over films grown using metal-catalyzed methods. The associated turn-on and threshold voltages, maximum current density, and emission current stability of the CNT films were measured using a standard vacuum tube diode test configuration. Although the samples tested did not demonstrate improved field emission characteristics when compared to values found in the literature for catalyst-grown CNT films, the data collected compares well with data in the literature and shows that further investigation is warranted regarding the emission capabilities of CNT films formed on SiC by surface decomposition. From the measured CNT data, the lowest turn-on electric field was found to be lower than 3.0 Vmicrometers, while exhibiting a high maximum current density of 4.25 mAsq cm at 6.7 Vmicrometers.