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- Morjan, I., et al.
(författare)
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Carbon nanotubes growth from C2H2 and C2H4/NH3 by catalytic LCVD on supported iron-carbon nanocomposites
- 2007
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Ingår i: Physica E: Low-Dimensional Systems and Nanostructures. - : Elsevier BV. - 1386-9477. ; 37:1-2, s. 26-33
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Tidskriftsartikel (refereegranskat)abstract
- We report about the synthesis of carbon nanotubes by catalytic LCVD (C-LCVD), using a CW CO2 laser and alternatively, C2H2/ C2H4/NH3 and C2H2/C2H4-containing gas mixtures. Different core-shell Fe-C nanocomposites (as synthesized and toluene extracted) were used employed as catalysts. The nanotubes grown from Fe-C residue demonstrate the lowest mean diameters. Prevalent curled and coiled morphologies are obtained for the CNTs grown in the presence of ammonia. (c) 2006 Elsevier B.V. All rights reserved.
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- Sveningsson, M., et al.
(författare)
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Raman spectroscopy and field-emission properties of CVD-grown carbon-nanotube films
- 2001
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Ingår i: Applied Physics a-Materials Science & Processing. ; 73, s. 409-418
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Tidskriftsartikel (refereegranskat)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 far 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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