| 1. |
- Dittmer, Staffan, 1970, et al.
(författare)
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In situ Raman studies of single-walled carbon nanotubes grown by local
- 2008
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 457
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Tidskriftsartikel (refereegranskat)abstract
- Using in situ Raman spectroscopy we investigate single wall carbon nanotube growth on Mo electrodes, using a highly localized resistive heating technique. Small diameter semiconducting single wall nanotubes grow very rapidly when the catalyst support is heated to a temperature of 800 C. The G/D ratio shows an interesting time-dependent behaviour. It first decreases, indicating the presence of amorphous carbon and then significantly increases again after ca. 5 min growth while retaining the position and shape expected for predominantly semiconducting carbon nanotubes.
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| 2. |
- Dittmer, Staffan, 1970, et al.
(författare)
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Local heating method for growth of aligned carbon nanotubes at low ambient temperature
- 2008
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Ingår i: Low Temperature Physics. - : AIP Publishing. - 1063-777X .- 1090-6517. ; 34:10, s. 834-838
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Tidskriftsartikel (refereegranskat)abstract
- We use a highly localised resistive heating technique to grow vertically aligned multiwalled nanotube films and aligned single-walled nanotubes on substrates with an average temperature of less than 100oC. The temperature at the catalyst can easily be as high as 1000 oC but an extremely high temperature gradient ensures that the surrounding chip is held at much lower temperatures, even as close as 1μm away from the local heater. We demonstrate the influence of temperature on the height of multi-walled nanotube films, illustrate the feasibility of sequential growth of single-walled nanotubes by switching between local heaters and also show that nanotubes can be grown over temperature sensitive materials such as resist polymer.
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| 3. |
- Dittmer, Staffan, 1970, et al.
(författare)
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Low ambient temperature CVD growth of carbon nanotubes
- 2006
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 84, s. 243-246
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Tidskriftsartikel (refereegranskat)abstract
- We show that good quality single-walled and multi-walled carbon nanotubes can be grown on CMOS-compatible metal electrodes at ambient room temperature using highly localised catalyst heating at nanostructured electrodes. The method is relatively straightforward and allows considerable flexibility in the kinds of devices that can be fabricated as well as allowing CVD nanotube growth to take place in the close vicinity of temperature-sensitive materials and devices.
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| 4. |
- Gromov, Andrei, 1959, et al.
(författare)
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Covalent Amino functionalisation of single walled carbon nanotubes
- 2005
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Ingår i: J. Materials Chem. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 15, s. 3334-3339
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Tidskriftsartikel (refereegranskat)abstract
- Chemical transformation of single-wall carbon nanotubes (SWNT), edge-terminated with carboxylic groups, to SWNT species with amino groups directly attached to the tube open ends has been performed. Different synthetic approaches have been investigated. The reaction products were characterised by FTIR, Raman spectroscopy, XPS and SEM.
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| 5. |
- Jonsson, Martin, et al.
(författare)
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DC plasma enhanced chemical vapour deposition growth of carbon nanotubes and nanofibres: in situ spectroscopy and plasma current dependence
- 2007
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 88, s. 261-267
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Tidskriftsartikel (refereegranskat)abstract
- Dc plasma-enhanced CVD growth of nanotubes and nanofibres is studied as a function of plasma power (3–40 W). The dependence of the nanotube/nanofibre morphology for growth on thin iron films and lithographically prepared individual nickel dots is investigated. In both cases, large differences in the morphology of the carbon nanostructures are observed as the plasma power is changed. In situ optical emission spectroscopy is used to obtain insight into the important parameters affecting the growth. The best growth results are found for intermediate plasma powers (15 W).
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| 6. |
- Jonsson, Martin, et al.
(författare)
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In situ growth rate measurements during plasma-enhanced chemical vapour deposition of vertically aligned multiwall carbon nanotube films
- 2007
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- In situ laser reflectivity measurements are used to monitor the growth of multiwalled carbon nanotube (MWCNT) films grown by DC plasma-enhanced chemical vapour deposition (PECVD) from an iron catalyst film deposited on a silicon wafer. In contrast to thermal CVD growth, there is no initial increase in the growth rate; instead, the initial growth rate is high (as much as 10 µm min-1) and then drops off rapidly to reach a steady level (2 µm min-1) for times beyond 1 min. We show that a limiting factor for growing thick films of multiwalled nanotubes (MWNTs) using PECVD can be the formation of an amorphous carbon layer at the top of the growing nanotubes. In situ reflectivity measurements provide a convenient technique for detecting the onset of the growth of this layer.
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| 7. |
- Kabir, Mohammad, 1974, et al.
(författare)
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Fabrication of individual, vertically aligned carbon nanofibres on metal substrates from prefabricated catalyst dots
- 2006
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 17:3, s. 790-794
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nanofibres (CNFs) of controlled diameter and length were grown on different metal substrates using plasma-enhanced chemical vapour deposition (PECVD). The diameter control of catalyst dots (and hence CNF diameter) was obtained by using the shot modulation technique in electron beam lithography. Catalyst dots of different sizes within arrays of different pitch were prepared and the dependence of the growth of vertically aligned CNFs on these parameters was studied for different metal underlayers. Good quality vertically aligned CNFs with a narrow length distribution were grown on Mo and W substrates. The structures grown on Nb substrates were significantly shorter for identical growth conditions and showed a lower nucleation rate. We demonstrate that through the shot modulation technique it is possible to control the diameter variation of CNFs from a single design geometry for the catalyst deposition. Individual VACNFs can be grown down to a pitch within the range 100–500 nm.
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| 8. |
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| 9. |
- Kabir, Mohammad, 1974, et al.
(författare)
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Plasma-enhanced chemical vapour deposition growth of carbon nanotubes on different metal underlayers
- 2005
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 16, s. 458-466
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Tidskriftsartikel (refereegranskat)abstract
- One important requirement for future applications of carbon nanotube electronic devices is the ability to controllably grow carbon nanotubes on metal electrodes. Here we show that it is possible to grow small diameter (<10 nm) vertically aligned carbon nanotubes on different metal underlayers using plasma-enhanced chemical vapour deposition. A crucial component is the insertion of a thin silicon layer between the metal and the catalyst particle. The electrical integrity of the metal electrode layer after plasma treatment and the quality of the metals as interconnects are also investigated.
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| 10. |
- Lee, SangWook, et al.
(författare)
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A three-terminal carbon nanorelay
- 2004
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Ingår i: Nano letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 4:10, s. 2027-2030
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Tidskriftsartikel (refereegranskat)abstract
- Three-terminal nanorelay structures were fabricated with multiwall carbon nanotubes (MWNTs). The nanotube relays were deflected by applying a gate voltage until contact (mechanical and/or electrical) was made with a drain electrode, thus closing the circuit. It was possible to achieve multiple switching cycles, showing that carbon nanotubes are suitable and practical systems for developing nanoelectromechanical devices of this kind.
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| 11. |
- Mattsson, M, et al.
(författare)
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Dielectrophoresis-induced separation of metallic and semiconducting SWNT in a continuous flow microfluidic system
- 2007
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Ingår i: Journal of Nanotechnology and Nanoscience. - : American Scientific Publishers. - 1533-4880. ; 7, s. 3431-3435
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Tidskriftsartikel (refereegranskat)abstract
- The AC dielectrophoresis-induced separation of metallic and semiconducting single-wall carbon nanotubes has been carried out in a continuous flow microfluidic system with isolated electrodes. The separation has been studied for single-wall carbon nanotube aqueous suspensions with ionic (sodium dodecylsulphate) and non-ionic (TritonX-100) surfactants. The efficiency of separation has been determined with the help of resonant Raman spectroscopy using various excitation energies. The prototype microfluidic cell presently shows somewhat inferior separation efficiency with respect to static dielectrophoretic filtering on arrays of microelectrodes but has potential for improvements. Factors influencing the separation efficiency and scaling up of the process are discussed.
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| 12. |
- Morjan, Raluca Elena, 1976, et al.
(författare)
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High growth rates and wall decoration of carbon nanotubes grown by plasma-enhanced chemical vapour deposition
- 2004
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 383/4, s. 385-390
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- DC plasma-enhanced chemical vapour deposition (PECVD) was used to grow films of aligned carbon nanotubes on a silicon wafer using Fe as catalyst and a C2H2/H2 gas mixture. The films were of high quality and showed an exceptionally high growth rate compared with other plasma growth techniques. For long growth times, the upper parts of the nanotubes developed additional outer graphite flakes. The onset of the ‘tube decoration’ correlates with a decrease in linear growth rate and can be related to the gradient of plasma parameters in the cathode sheath.
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| 13. |
- Morjan, Raluca Elena, 1976, et al.
(författare)
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Selective growth of individual multiwalled carbon nanotubes
- 2004
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Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 4:6, s. 591-594
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Tidskriftsartikel (refereegranskat)abstract
- Growth of individual, vertically aligned multiwalled carbon nanotubes (VACNT) on patterned Si wafers using dc plasma-enhanced CVD is described. The selective growth of individual VACNT within larger holes etched in Si is demonstrated for the first time.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Svensson, Johannes, 1978, et al.
(författare)
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Field emission induced deformations in SiO2 during CVD growth of carbon nanotubes
- 2006
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 243, s. 3524-3527
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Tidskriftsartikel (refereegranskat)abstract
- The application of an electric field while growing carbon nanotubes with CVD can induce deformations in the SiO2 substrate. The effect is attributed to field emission from the tubes and Marangoni convection in a small molten SiO2 region underneath the tubes. Postgrowth deformation has been performed as well as large scale deformations using the collective effect of many field emitters. The porosity of one type of deformation is also examined and discussed.
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| 18. |
- Svensson, Johannes, 1978, et al.
(författare)
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Marangoni effect in SiO(2) during field-directed chemical vapor deposition growth of carbon nanotubes
- 2006
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Ingår i: Physical Review B. - 0163-1829. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Intense local heating of SiO2 is shown to occur during chemical vapor deposition growth of single-walled carbon nanotubes in the presence of an electric field. This gives rise to the Marangoni effect where strong convection currents are induced in the molten SiO2 layer. Nanoscale trenches and bumps are formed in the insulating layer directly below the growing nanotube.
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| 19. |
- Yao, Yiming, 1957, et al.
(författare)
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Cross sectional TEM investigation of Ni-catalysed carbon nanotube films grown by plasma enhanced CVD
- 2005
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 219, s. 69-75
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nickel-catalysed multiwall carbon nanotubes synthesized by plasma-enhanced chemical vapour deposition on a silicon substrate with acetylene and ammonia at 700 °C have been characterized by high-resolution and analytical transmission electron microscopy. The nucleation of the carbon nanotubes occurs as a consequence of the carburization and dusting of supported preformed nickel- and silicon-rich particles. This process yields disintegrated silicon-containing nickel particles dispersed in dome-shaped carbon islands adherent to the substrate. The particles act as catalysts for tube growth, resulting in aligned multiwall carbon nanotubes with a bamboo-like structure anchored to the dome-shaped carbon islands. The bottom part of the carbon islands contains bundles of graphene sheets orientated parallel to the substrate. The nanotubes are capped with fcc nickel particles containing dissolved silicon. Most of these particles have a conical shape orientated with a <110> direction along the tube growth axis, and with {110} and {111} planes as exposed faces.
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| 20. |
- Yao, Yiming, 1957, et al.
(författare)
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Nucleation and aligned growth of multi-wall carbon nanotube films during thermal CVD
- 2007
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 45, s. 2065-2071
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The development during early growth of a multi-wall carbon nanotube film by thermal CVD with acetylene (C2H2) and hydrogen at 750 °C has been characterized in detail by cross-section transmission electron microscopy. The studies provide information on the nanotube growth mechanisms and the complex catalyst transformations that are essential for the onset of different growth stages. An initial random growth catalysed by supported particles is followed by aerosol growth of aligned tubes. This results in a two-layered film structure, where a film of aligned nanotubes is lifting up an initially formed nanotube network from the substrate.
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| 21. |
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