Abstract.
Carbon-nanotube films are very efficient cathodes for field-emission devices. This study presents a comprehensive comparison between structural, spectroscopic and field-emission properties of films of aligned and non-aligned multi-wall nanotubes (MWNTs) which are grown by thermal chemical vapour deposition. Three types of films are investigated: vertically aligned MWNTs with clean and coated nanotube side walls as well as non-aligned MWNT films. Raman spectra taken on the aligned MWNT films consist of many lines of first-, second- and third-order signals. Several lines are reported here for the first time for MWNTs. The presence of the surface coating leads to a decrease and broadening of the higher-order signals as well as an increase in the disorder-induced contributions in the first-order regime. The aligned MWNT films have excellent field-emission properties with very high emission current densities and low turn-on and threshold fields. The presence of a surface coating has no impact on the efficiency of the field-emission process. Films of non-aligned MWNTs show considerably reduced electron-emission current densities and larger critical fields.
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Received: 25 April 2001 / Accepted: 30 May 2001 / Published online: 25 July 2001
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Sveningsson, M., Morjan, RE., Nerushev, O. et al. Raman spectroscopy and field-emission properties of CVD-grown carbon-nanotube films . Appl Phys A 73, 409–418 (2001). https://doi.org/10.1007/s003390100923
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DOI: https://doi.org/10.1007/s003390100923