Discharge characteristics of a nano-sized electrode with aligned carbon nanotubes grown on a tungsten whisker tip under various gas conditions

Abstract

Vertically aligned multiwalled carbon nanotubes were grown on a tungsten (W) tip by thermal chemical vapor deposition (CVD), applying a negative biasing voltage to the W tip in a pin-plate electrodes configuration. The carbon nanotube(CNT) electrodes, due to their nano-sized tip radii, create very high electric fields, and reduce significantly the breakdown voltage. Comparing the CNTs-grown W tip electrode to the W tip electrode, the ignition voltage for the former case decreased from 230 V to 181 V, while the saturation current increased from 12 μA to 20 μA. These results are attributed to a relatively high field enhancement factor β~960 of the CNTs electrodes compared to β~60 for the simple W tip.There are also significant differences between the W tip electrodes with and without CNTs in the values of the igniting voltage and discharge current, when the W tips were used as cathode.. : 52.80.-s, 52.90.+z, 81.07.-b PACS

Field-emission-assisted approach to dry micro-electro-discharge machining of carbon-nanotube forests

“…The increased discharge current with the reverse polarity is also consistent with the results reported in Ref. 18.…”

“…Another study shows that discharge currents (in a corona phase) with CNT-forest cathodes are 6-7Â larger than those with tungsten cathodes. 18 The discharge current densities calculated from Fig. 2(a) at 10 V for the normal and reverse polarities (assuming that the current is uniformly distributed over the bottom surface of the 93-lm-diameter electrode) are 10.3 A/cm 2 and 29.5 A/cm 2 , respectively, giving a 2.86Â increase in the discharge current when the reverse polarity or the CNT-forest cathode is used.…”

“…Because of their extremely small tips with nanometer radii and high aspect ratios, CNTs are known to significantly enhance an applied electric field and thus have excellent electron emission properties. In fact, CNT cathodes were reported to reduce gas breakdown voltage while increasing the discharge current compared to tungsten cathodes; 18 although the set-up and the ranges of the breakdown voltage a)…”

Dry micro-electro-discharge machining of carbon-nanotube forests using sulphur-hexafluoride

“…Because of their extremely small tips with nanometer radii and high aspect ratios, CNTs are known to have excellent electron field-emission properties compared to the tungsten tip (a typical material used as EDM tool) [12]. It has recently been found that reverse-polarity EDM of CNT forests that are defined as the cathode in air ambient enhances the patterning tolerances and quality with decreased discharge energies [6].…”

Microelectric Discharge Plasma: Characterization and Applications

“…There are several reports with different anode-cathode configurations such as planer electrodes [8], flat and point electrode [9], wire electrode and plate electrode [10], rod electrodes [11], co-planer electrodes [12], and many more. Above said configurations are mostly the combinations of metals.…”