Field electron emission properties of vertically aligned carbon nanotubes deposited on a nanostructured porous silicon template: The hidden role of the hydrocarbon/catalyst ratio

Field Emission from Hybrid Diamond-like Carbon and Carbon Nanotube Composite Structures

“…From the as-grown VACNT, E th was ∼3.2 V μm −1 , consistent with previously published values for CNT arrays. 32,33 E th for the wetted VACNT decreased to ∼1.8 V μm −1 , and for VACNT/DLC E th ∼2.1 V μm −1 . These data are all consistent with the F−N model for electron emission via quantum mechanical tunnelling through a potential barrier.…”

“…37,38 Note that the geometrical β (∼2000) calculated from (h/r) using the height (h) and radius (r) of the individual nanotubes is considerably lower than the values calculated from these F−N plots, a finding which is often reported for field-emission from VACNT forests. 32 There are a number of possible suggested reasons for this difference, including (a) perturbations of the electric field because of the experimental configuration, especially the interelectrode separation, 39 (b) the emission being a multistage process from many adjacent emitting tips rather than being from one isolated tip, 40 (c) electrical and thermal conduction effects from the surrounding VACNT forest, 36 and/or (d) high field enhancement at the nanotube−substrate−vacuum triple junction at the base of the CNTs causing electrons to be emitted directly into the vacuum. 32 Thus, it is clear that although the absolute magnitude of β values derived from F−N plots should be regarded with caution, 38 so long as they were measured under identical conditions then sensible deductions can be made based on their relative values.…”

Field Emission Characteristics of the Structure of Vertically Aligned Carbon Nanotube Bundles

“…Figure 3 a presents the J – E curves of the synthesized VACNT bundles. The turn-on electric fields ( E to ) corresponding to the current density of 10 −2 mA cm −2 [ 13 , 14 ] for samples A, B, C, and D were approximately 2.0, 2.8, 1.6, and 2.5 V μm −1 , respectively. Figure 3b shows the FN plots of the synthesized samples.…”

Field Emission Characteristics of the Structure of Vertically Aligned Carbon Nanotube Bundles

“…Figure 3a presents the J-E curves of the synthesized VACNT bundles. The turn-on electric fields (E to ) corresponding to the current density of 10 −2 mA cm −2 [13,14] for samples A, B, C, and D were approximately 2.0, 2.8, 1.6, and 2.5 V μm −1 , respectively. Figure 3b shows the FN plots of the synthesized samples.…”