Article ID Journal Published Year Pages File Type
702743 Diamond and Related Materials 2009 5 Pages PDF
Abstract

Conical carbon nanotubes (CCNTs) with unique structural characteristics arising from their tapered morphologies compared to uniform diameter carbon nanotubes, have been shown to exhibit enhanced field emission properties and support high current densities. Specifically, several CCNT arrays with different morphological characteristics (tip radius, aspect ratio, density and wall structure) were synthesized by variations in the process parameters using a microwave plasma chemical vapor deposition (MWCVD) reactor. The field emission characteristics for a CCNT array sample with a tip radius of 5 nm, density of 108/cm2 and having the highest aspect ratio exhibited a low turn-on electric field (< 0.7 V/μm) and a high field enhancement factor (β > 7500). Other samples with lower emission characteristics were attributed either to the presence of field screening effect resulting from higher CCNT density or due to the corresponding tip and wall characteristics.

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Physical Sciences and Engineering Engineering Electrical and Electronic Engineering
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