Article

Applied Physics A

, Volume 73, Issue 4, pp 409-418

First online:

Raman spectroscopy and field-emission properties of CVD-grown carbon-nanotube films

  • M. SveningssonAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden
  • , R.-E. MorjanAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden
  • , O.A. NerushevAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden
  • , Y. SatoAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden
  • , J. BäckströmAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden
  • , E.E.B. CampbellAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden
  • , F. RohmundAffiliated withDepartment of Experimental Physics, Gothenburg University and Chalmers University of Technology, 41296 Gothenburg, Sweden

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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.

PACS: 81.07.De; 85.45.Db; 78.30.Na