Field emission characteristics of metal nanoparticle-coated carbon nanowalls

Kaneko, Yoshiki; Terada, Kazuhiro; Teii, Kungen

doi:10.1088/1361-6528/ab6748

Cited by 8 publications

(4 citation statements)

References 39 publications

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“…The other techniques are hybridization of CNWs and other nanomaterials. These include decoration of CNWs with metal nanoparticles, , formation of CNW/nanocrystalline diamond composite films, − formation of CNW/CNT hybrid films, and coating of CNWs on Si microspikes . Diamond possesses a number of outstanding properties such as high hardness, high thermal conductivity, and high carrier mobility and can maintain negative electron affinity stably even in ambient air .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Field Emission from Ultrananocrystalline Diamond-Decorated Carbon Nanowalls Prepared by a Self-Assembly Seeding Technique

Huang

Harajiri

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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Vertically aligned nanographite structures, the so-called carbon nanowalls (CNWs), are decorated with ultrananocrystalline diamond particles by an electrostatic self-assembly seeding technique, followed by short-term growth in plasma chemical vapor deposition, to enhance field emission efficiency and stability. A nanodiamond suspension diluted with a dispersion medium with high wettability on CNWs enables seeding of diamond nanograins consisting of nanoparticles of 3–5 nm in diameter on CNWs with high uniformity and minimal aggregation and control of their number density. The field emission turn-on field depends upon the density of diamond nanograins and decreases from 3.0 V μm–1 for bare CNWs to 1.8 V μm–1 for diamond-decorated CNWs together with about an order of magnitude increase in current density. Finite element modeling indicates that only a part of decorating diamond located at the top of nanowalls actually contributes to field amplification and emission. The diamond-decorated CNWs show also higher emission stability with much larger time constants of current degradation than the bare CNWs for long-term duration. The enhanced emission efficiency is explained by larger field amplification rather than lowering of the tunneling barrier, while the enhanced emission stability is attributed to the higher robustness of diamond.

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Section: Introductionmentioning

confidence: 99%

Enhanced Field Emission from Ultrananocrystalline Diamond-Decorated Carbon Nanowalls Prepared by a Self-Assembly Seeding Technique

Huang

Harajiri

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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“…Thin-film materials containing high-aspect-ratio structures, such as carbon nanotubes (CNTs) [7][8][9][10], various nanowires [11][12][13] and nanowalls [14][15][16][17], are considered the most suitable for creating FE cathodes for EP thrusters [3]. Electrons can be released from such nanostructures by applying a relatively low voltage due to strong field enhancement at their apexes or sharp corners.…”

Section: Introductionmentioning

confidence: 99%

Nano-graphite field-emission cathode for space electric propulsion systems

et al. 2022

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Improving the thruster efficiency is a crucial challenge for the development of space electric propulsion systems, especially advanced air-breathing thrusters utilizing the surrounding rarefied atmosphere as fuel. A significant reduction in thruster power consumption can be achieved by using field emission (FE) cathodes that do not require heating and have the highest energy efficiency. In this work, we study FE from nano-graphite thin films, consisting of carbon nanostructures with a high aspect ratio, and demonstrate their suitability for use in the space electric propulsion systems. The films shown appropriate FE characteristics in a wide range of gas pressures at high current loads in constant and pulsed operation modes. Based on the obtained experimental results, nano-graphite cathodes were employed for the design of an electron gun with increased reliability and minimized energy losses associated with electron extraction. The possibility of using such a gun in a specific air-breathing satellite operating in low Earth orbits is demonstrated.

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“…One is chemical/physical modification of CNWs such as surface nitridation for increasing sp 2 domain size, crystallinity, and conductivity [15] and increasing graphitization for a transition from semiconducting to semi-metallic conduction [12]. The other is combination of CNWs with other nanomaterials such as decoration of CNWs with metal nanoparticles [16,17] and carbon nanotubes [18], formation of CNWs/nanocrytalline diamond composite films [19][20][21][22][23], and coating of CNWs on Si microspikes [24]. Diamond is potentially superior to metals for the purpose of materials combination as it has high hardness, high thermal conductivity, high chemical inertness, and even negative electron affinity.…”

Section: Introductionmentioning

confidence: 99%

Control of electrostatic self-assembly seeding of diamond nanoparticles on carbon nanowalls

Huang¹,

Wu²,

Hijiya³

et al. 2021

Nanotechnology

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Seeding of diamond nanoparticles on vertically-aligned multi-layer graphene, the so-called carbon nanowalls (CNWs), is studied by using deionized water, ethylene glycol, ethanol, and formamide as dispersion mediums. Detonation nanodiamond particles show the smallest mean size and size distribution with a high positive zeta potential when dispersed in ethanol. The contact angle of ethanol on CNWs is almost zero degree, confirming highly wetting behaviour. The diamond nanoparticles dispersed in ethanol are distributed the most uniformly with minimal aggregation on CNWs as opposed to those dispersed in other liquids. The resulting diamond nanoparticle-seeded CNWs, followed by short-term growth in microwave plasma chemical vapor deposition, show a marked decrease in field emission turn-on field down to 1.3 V μm−1 together with a large increase in current density, compared to bare CNWs without diamond seeding. The results provide a way to control the density, size, and uniformity (spacing) of diamond nanoparticles on CNWs and should be applied to fabricate hybrid materials and devices using nanodiamond and nanocarbons.

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Field emission characteristics of metal nanoparticle-coated carbon nanowalls

Cited by 8 publications

References 39 publications

Enhanced Field Emission from Ultrananocrystalline Diamond-Decorated Carbon Nanowalls Prepared by a Self-Assembly Seeding Technique

Enhanced Field Emission from Ultrananocrystalline Diamond-Decorated Carbon Nanowalls Prepared by a Self-Assembly Seeding Technique

Nano-graphite field-emission cathode for space electric propulsion systems

Control of electrostatic self-assembly seeding of diamond nanoparticles on carbon nanowalls

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