Iron oxide-coated MWCNTs nanohybrid field emitters: a potential cold cathode for next-generation electron sources
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Iron oxide-coated MWCNTs nanohybrid field emitters: a potential cold cathode for next-generation electron sources Shabeena Saifi1, Shama Parveen1, Sunny Khan1, Javid Ali1, M. Husain1, and M. Zulfequar1,* 1
Department of Physics, Jamia Millia Islamia, New Delhi, India
Received: 19 March 2020
ABSTRACT
Accepted: 21 August 2020
In this paper, we have reported that the field emission properties of multiwall carbon nanotubes (MWCNTs) were significantly increased by decorating their surface by iron oxide nanoparticles. MWCNTs were prepared on silicon substrate through low-pressure chemical vapour deposition using acetylene as source gas. The iron oxide nanoparticles were grown on the surface of MWCNTs by thermal evaporation technique. Modified surface morphologies of the prepared films were characterized through field emission scanning electron microscope (FESEM), Raman spectroscopy and X-ray diffraction. A significant change in current density, stability and turn-on voltage has been observed in iron oxide-coated MWCNT films. Decoration of iron oxide nanoparticles reduces turn-on voltage from 4 to 3.4 V/lm, while current density increases from 10.15 to 33.26 mA/cm2. For practical MWCNT-based field emission devices, it is necessary to improve the emission current density and stability. The excellent field emission parameters are obtained and calculated which make them useful for high-performance field emission-based devices. The mechanism of emission of electrons is well described by the Fowler Nordheim theory.
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Springer Science+Business
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1 Introduction Carbon nanotubes (CNTs) are among one of the promising materials within the carbon family which are gaining attention of the researchers since its discovery in 1991 by Iijima [1]. CNTs due to its unique properties such as high aspect ratio [2], high electrical conductivity [3], good mechanical stiffness [4], high tensile strength [5], low thermal expansion coefficient
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https://doi.org/10.1007/s10854-020-04304-8
[6] and a small radius of curvature at the cap [7] are considered to be ideal candidate for various applications in the field of optoelectronic devices. CNTs as efficient electron emitter’s source is an attractive source of electron for next-generation vacuum nanoelectronic devices based on CNT as electron field emission cathodes. CNTs as cathodes operate at very low voltage which opens its use in developing miniature devices for diverse applications such as in
J Mater Sci: Mater Electron
flat displays [8, 9], X-ray tubes [10–12], microwave amplifiers [13, 14], and in lighting tubes [15, 16]. Conventional electron source based on thermionic emission has drawbacks due to high consumption power and deterioration of emitter due to long-term heating [17]. So, to overcome these problems, CNTs as field emitters are in great demand. CNTs act as a cold cathodes and have advantages over hot cathodes as it can be operated at low temperature and requires less power con
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