Effect of length and spacing of vertically aligned carbon nanotubes on field emission properties

Jo, Sung Ho; Tu, Yuan‐Kuang; Huang, Zhongping; Carnahan, David; Wang, D. Z.; Z, Ren

doi:10.1063/1.1576310

Cited by 258 publications

(155 citation statements)

References 14 publications

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“…Nanotube production involves the widespread use of transition metal ͑TM͒ catalysts such as Ni, Co, or Fe, and field emission experiments have shown that CNTs, regardless of whether they are diode or triode type, are excellent field electron emitters with high current density under a relative low electric field. [1][2][3][4][5][6][7][8][9][10] The emission behavior has been related to the localized electronic states at the nanotube tips, space-charge effects, and other adsorbates. Here, note that in most cases, one cannot rule out the effect of the existence of catalytic metals on the tip ends of CNTs or in outer sites such as bridge and atop sites on the C-C bonds.…”

mentioning

confidence: 99%

Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

Lee

Kim

et al. 2006

Applied Physics Letters

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We report the electron paramagnetic resonance characteristics of catalytic residues for in situ grown carbon nanotube field electron emitter and present direct evidence that field electron emission in carbon nanotube sheets grown on various catalytic nanodots/SiO2-coated Si substrate with low-pressure chemical vapor deposition is influenced by the magnetism of catalytic metals and thus the electrical properties of the nanotubes. The nanotubes with weak trace of ferromagnetism, which originated from the catalysts, show lower turn-on emission field and higher electron emission current than those with distinct ferromagnetic properties. A strong relationship between the ferromagnetism of nanocrystalline catalysts and field electron emission characteristics of nanotubes can be utilized for the development of an efficient carbon nanotube based-field electron emitter.

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mentioning

confidence: 99%

Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

Lee

Kim

et al. 2006

Applied Physics Letters

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“…It has been shown that reducing the density of MWNTs in the bundles is one way to decrease the turn-on field of the MWNT film. 29 In addition, Fujii et al 30 reported that optimizing the length of MWNT bundles with respect to the distance between bundles reduced the turn-on field significantly. This finding can be used to modify the MWNT pattern ͑and length͒ on the cathode of the microion source devices.…”

Section: E Increasing the Efficiency Of The 4-panel Microion Sourcementioning

confidence: 99%

Analysis of 3-panel and 4-panel microscale ionization sources

Natarajan

Piascik

Gilchrist

et al. 2010

Journal of Applied Physics

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Two designs of a microscale electron ionization ͑EI͒ source are analyzed herein: a 3-panel design and a 4-panel design. Devices were fabricated using microelectromechanical systems technology. Field emission from carbon nanotube provided the electrons for the EI source. Ion currents were measured for helium, nitrogen, and xenon at pressures ranging from 10 −4 to 0.1 Torr. A comparison of the performance of both designs is presented. The 4-panel microion source showed a 10ϫ improvement in performance compared to the 3-panel device. An analysis of the various factors affecting the performance of the microion sources is also presented. SIMION, an electron and ion optics software, was coupled with experimental measurements to analyze the ion current results. The electron current contributing to ionization and the ion collection efficiency are believed to be the primary factors responsible for the higher efficiency of the 4-panel microion source. Other improvements in device design that could lead to higher ion source efficiency in the future are also discussed. These microscale ion sources are expected to find application as stand alone ion sources as well as in miniature mass spectrometers. © 2010 American Institute of Physics. ͓doi:10.1063/1.3429220͔ I. APPLICATIONS AND LITERATURE REVIEW OF MICROSCALE ION SOURCES A. Introduction to ionization sourcesIon sources are important scientific devices that find application in a variety of areas. They are used in particle accelerators, ion implantation systems for the semiconductor industry, semiconductor processes such as reactive ion etching, giant neutral beam injectors in experimental fusion reactor devices, and in analytical instruments such as mass spectrometers. 1Gas phase ionization techniques include electron ionization ͑EI͒, field ionization, and chemical ͑or charge transfer͒ ionization. Electron impact ionization or electron bombardment ionization is the process in which an electron with suitable energy collides with a neutral atom or molecule resulting in the formation of an ion and an electron. In field ionization, an electron is removed by tunneling from the molecule in the presence of a strong electric field, creating an ion. Field ionization tends to result in fewer fragmentation events than does EI. Chemical ionization uses a reagent gas, such as methane. The reagent gas is ionized using an EI source, for example, and then reacted with the analyte molecules, ionizing them in a lower energy state, also resulting in less fragmentation than in EI.Liquid and solid phase ionization techniques are most commonly used for mass spectroscopy. Liquid phase techniques include atmospheric pressure chemical ionization, field desorption, and electrospray ionization ͑ESI͒. These techniques require the analyte compound to be nebulized into the gas phase and the solvent removed through a series of stages of increasing vacuum ͑typically atmosphere to 10 −6 Torr or greater͒ as the ions travel into the mass spectrometer. Solid phase techniques include matrix-assisted laser des...

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“…Related studies have focused on exploring highly efficient field-emitting materials and their nanotechnology [12][13][14][15][16][17]. Although the field emitters reported to date require a threshold electric field (E th ) of 2∼3 V/µm at minimum to produce a technologically useful current density of 10 mA/cm 2 [18][19][20][21][22][23][24], it is important to lower the E th to achieve practically applicable field electron emitters that operate with a low power consumption.…”

Section: B Towards Highly Efficient Field Electron Emittermentioning

confidence: 99%

Synthesis of Nanostructured Hybrid between Carbon Nanotube and Inorganic Material towards Nanodevice Application

Katayama

Honda

Ikuno

et al. 2004

e-J. Surf. Sci. Nanotech.

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In this review, we demonstrate the device-oriented synthesis of carbon nanotubes (CNTs), by taking an energy storage device and a field electron emitter as examples. As one of the most desirable approaches to fabricating nanostructured hybrids between carbon nanotubes and inorganic materials, we present a method of coating carbon nanotubes with inorganic materials in multishell form, and its application to nanoprobe fabrication.

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Effect of length and spacing of vertically aligned carbon nanotubes on field emission properties

Cited by 258 publications

References 14 publications

Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

Analysis of 3-panel and 4-panel microscale ionization sources

Synthesis of Nanostructured Hybrid between Carbon Nanotube and Inorganic Material towards Nanodevice Application

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