| 1. |
- Yao, Yiming, 1957, et al.
(författare)
-
Nucleation and aligned growth of multi-wall carbon nanotube films during thermal CVD
- 2007
-
Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 45, s. 2065-2071
-
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.
|
|
| 2. |
- Jonsson, Martin, et al.
(författare)
-
DC plasma enhanced chemical vapour deposition growth of carbon nanotubes and nanofibres: in situ spectroscopy and plasma current dependence
- 2007
-
Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 88, s. 261-267
-
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).
|
|
| 3. |
- Jonsson, Martin, et al.
(författare)
-
In situ growth rate measurements during plasma-enhanced chemical vapour deposition of vertically aligned multiwall carbon nanotube films
- 2007
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 18
-
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.
|
|
| 4. |
- Mattsson, M, et al.
(författare)
-
Dielectrophoresis-induced separation of metallic and semiconducting SWNT in a continuous flow microfluidic system
- 2007
-
Ingår i: Journal of Nanotechnology and Nanoscience. - : American Scientific Publishers. - 1533-4880. ; 7, s. 3431-3435
-
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.
|
|
| 5. |
- Wang, Teng, 1983, et al.
(författare)
-
Low temperature transfer and formation of carbon nanotube arrays by imprinted conductive adhesive
- 2007
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:9
-
Tidskriftsartikel (refereegranskat)abstract
- This letter demonstrates the transfer and formation of aligned carbon nanotube (CNT) arrays at low temperature by imprinted conductive adhesive. A thermoplastic isotropic conductive adhesive is patterned by an imprint and heat transfer process. The CNTs grown by thermal chemical vapor deposition are then transferred to another substrate by the conductive adhesive, forming predefined patterns. The current-voltage response of the transferred CNT bundles verifies that good electrical connection has been established. This process can enable the integration of CNTs into various temperature-sensitive processeses and materials.
|
|
| 6. |
- Hansen, Klavs, 1958, et al.
(författare)
-
Competition between fusion and intra-cluster fusion in highly excited fullerene clusters
- 2007
-
Ingår i: Israel Journal of Chemistry. - 0021-2148. ; 47
-
Tidskriftsartikel (refereegranskat)abstract
- The occurrence of intra-cluster fusion of fullerene molecules inside van der Waals bound fullerene clusters can be observed following femtosecond laser excitation. We show that the fusion reaction competes with the fission of multiply charged clusters. Energetic barriers to the reaction of at least 85 eV have to be overcome, similar to the energetic barriers to molecular fusion observed in fullerene ion–neutral fullerene collision experiments.
|
|
| 7. |
- Hansen, Klavs, 1958, et al.
(författare)
-
ISSPIC13 proceedings - Preface
- 2007
-
Ingår i: Eur.Phys.J D. - 1434-6060. ; 43
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 8. |
|
|
| 9. |
- Lee, SangWook, et al.
(författare)
-
In situ Raman measurements of suspended individual single-walled carbon nanotubes under strain
- 2007
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 7, s. 2590-2595
-
Tidskriftsartikel (refereegranskat)abstract
- We present a technique for in situ Raman measurements of suspended individual single-walled carbon nanotubes (SWNTs) under strain. We observe a strong change in the radial breathing mode intensity with increasing strain as the nanotube moves out of (or into) resonance, and for strain greater than 2%, there is a clear irreversible upshift in the G-mode frequencies accompanied by an increase in intensity of a broad peak at a position associated with the D mode. For lower strain, the G-mode peaks (A1, E1, and E2) do not change significantly in position but change in relative intensity.
|
|
| 10. |
- Popok, Vladimir, 1966, et al.
(författare)
-
Conductance and polarisability of C60 films
- 2007
-
Ingår i: Journal of Nanoscience and Nanotechnology. ; 7:4-5, s. 1434-1438
-
Tidskriftsartikel (refereegranskat)abstract
- Thin films of C60 deposited in vacuum are studied using current-voltage (I-V) measurements and atomic force microscopy (AFM). In situ electrical measurements give an average resistivity of ca. 30 MΩcm for the as-deposited films at room temperature. The I-V dependences are found to correspond to ohmic behaviour but they have a hysteresis shape attributed to remnant polarisation due to the domain structure of the films. AFM images show a grainy surface morphology for the deposited C60. Temperature dependent measurements in the range 290-365 K provide evidence for a variable range hopping mechanism of conductance with an activation energy of 0.8-1.0 eV. With further temperature increase the C60 films restructure leading to an increase in grain size and a change of the electrical properties with I-V dependences showing Schottky barrier formation. The effect of oxygen on the conductance of the C60 films under their exposure to an ambient atmosphere is considered and discussed.
|
|
