Enhancement of electron field emission from carbon nanofiber bundles separately grown on Ni catalyst in Ni–Cr alloy

Shimoi, Norihiro; Tanaka, Shun–ichiro

doi:10.1016/j.carbon.2008.12.050

Cited by 18 publications

(16 citation statements)

References 17 publications

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“…The major obstacle in controlling the diameter of CNTs, particularly for small diameter SWCNTs, is the migration of the catalyst material resulting in unwanted nanoparticle aggregation. To prevent or minimize this effect, Cr was chosen because the previous reports showed that it could suppress the catalyst migration by acting as spacer 30 or dispersant 31 between active catalysts or by reacting with the Al 2 O 3 buffer layer to bind the catalyst nanoparticles 32 . After synthesis, the diameters were characterized and plotted as a function of each alloy in a ternary plot with colors representing the resulting SWCNT average diameters for forests, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, for Fe-Ni-Cr alloy, the catalyst nanoparticles showed a much smaller change in size and density, indicating that the presence of Cr suppressed the nanoparticle aggregation. The actual mechanism behind this remains uncertain, but a literature survey showed two different reports believed that Cr could act as spacer 30 or dispersant 31 between active catalysts. In a separate report, the Cr was thought to bind with the Al 2 O 3 buffer layer to resist the migration 32 .…”

Section: Discussionmentioning

confidence: 99%

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Diameter control of single-walled carbon nanotube forests from 1.3–3.0 nm by arc plasma deposition

Chen

Seki

Kimura

et al. 2014

Sci Rep

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We present a method to both precisely and continuously control the average diameter of single-walled carbon nanotubes in a forest ranging from 1.3 to 3.0 nm with ~1 Å resolution. The diameter control of the forest was achieved through tuning of the catalyst state (size, density, and composition) using arc plasma deposition of nanoparticles. This 1.7 nm control range and 1 Å precision exceed the highest reports to date.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Diameter control of single-walled carbon nanotube forests from 1.3–3.0 nm by arc plasma deposition

Chen

Seki

Kimura

et al. 2014

Sci Rep

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show abstract

“…However, any SiNx that forms on the substrate is likely to be removed due to the constant flux of energetic ions bombarding the substrate directly, which explains the result in curve 1. Since sidewall conduction is of little interest for the field emission applications of such CNFs 27 where electron transport occurs internally within the CNF body, in-situ nanomanipulation measurements performed here uniquely suggest that CNFs synthesized directly on Si are unsuitable for low voltage dc NEMS applications.…”

Section: Electrical Actuation In Vertically Oriented Carbon Nanofibersmentioning

confidence: 95%

Carbon-based nano-electro-mechanical systems

et al. 2010

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We provide an overview of our work where carbon-based nanostructures have been applied to twodimensional (2D) planar and three-dimensional (3D) vertically-oriented nano-electro-mechanical (NEM) switches. In the first configuration, laterally oriented single-walled nanotubes (SWNTs) synthesized using thermal chemical vapor deposition (CVD) were implemented for forming bridge-type 2D NEMS switches, where switching voltages were on the order of a few volts. In the second configuration, vertically oriented carbon nanofibers (CNFs) synthesized using plasma-enhanced (PE) CVD have been explored for their potential application in 3D NEMS. We have performed nanomechanical measurements on such vertically oriented tubes using nanoindentation to determine the mechanical properties of the CNFs. Electrostatic switching was demonstrated in the CNFs synthesized on refractory metallic nitride substrates, where a nanoprobe was used as the actuating electrode inside a scanning-electron-microscope. The switching voltages were determined to be in the tens of volts range and van der Waals interactions at these length scales appeared significant, suggesting such structures are promising for nonvolatile memory applications. A finite element model was also developed to determine a theoretical pull-in voltage which was compared to experimental results.

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“…A helicon-wave-assisted PECVD was used to induce CNF growth at a low temperature [28]. CNFs synthesized by this method stand in bundles and have been characterized as arrayed with space between adjacent bundles.…”

Section: Formation Of Ni-cr Alloy By Cosputteringmentioning

confidence: 99%

Optimized Distribution and Morphology of Carbon Nanofibers for a Field Emitter Grown by Nickel and Chromium Cosputtering

Shimoi¹,

Tanaka²

2013

MSA

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To obtain a high field emission (FE) current with a low driving voltage, it is important to control and optimize carbon nanofiber (CNF) array patterns for FE. While there have been various means for controlling CNF array patterns reported over the past few decades, array patterning using lithography is the method typically used to control CNF morphology. Because lithography uses many masks and is costly, it is necessary to establish a simpler process. In this study, the grain size and distribution of catalysts with phase separation were controlled. A system which controls the morphology of small bundles of CNFs was constructed with the distance between the bundles kept constant in order to obtain a higher FE current. The Ni catalyst layer for forming the CNF morphology was separated by noncatalytic Cr grains formed by cosputtering. As a result, it was possible to control the Ni content, the grain size and synthesis density of CNFs in the alloy with a varying number of nickel pellets placed on the chromium target. This method is an epochmaking CNF patterning technique very different from lithography.

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Enhancement of electron field emission from carbon nanofiber bundles separately grown on Ni catalyst in Ni–Cr alloy

Cited by 18 publications

References 17 publications

Diameter control of single-walled carbon nanotube forests from 1.3–3.0 nm by arc plasma deposition

Diameter control of single-walled carbon nanotube forests from 1.3–3.0 nm by arc plasma deposition

Carbon-based nano-electro-mechanical systems

Optimized Distribution and Morphology of Carbon Nanofibers for a Field Emitter Grown by Nickel and Chromium Cosputtering

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