The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
J Robertson - One of the best experts on this subject based on the ideXlab platform.
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catalytic chemical Vapor Deposition of single wall carbon nanotubes at low temperatures
Nano Letters, 2006Co-Authors: M Cantoro, Stephan Hofmann, Caterina Ducati, Simone Pisana, V Scardaci, A Parvez, Andrea Ferrari, A M Blackburn, Kaiyou Wang, J RobertsonAbstract:We report surface-bound growth of single-wall carbon nanotubes (SWNTs) at temperatures as low as 350 °C by catalytic chemical Vapor Deposition from undiluted C2H2. NH3 or H2 exposure critically facilitates the nanostructuring and activation of sub-nanometer Fe and Al/Fe/Al multilayer catalyst films prior to growth, enabling the SWNT nucleation at lower temperatures. We suggest that carbon nanotube growth is governed by the catalyst surface without the necessity of catalyst liquefaction.
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low temperature growth of carbon nanotubes by plasma enhanced chemical Vapor Deposition
Applied Physics Letters, 2003Co-Authors: Stephan Hofmann, Caterina Ducati, J Robertson, B KleinsorgeAbstract:Vertically aligned carbon nanotubes were grown at temperatures as low as 120 °C by plasma-enhanced chemical Vapor Deposition. A systematic study of the temperature dependence of the growth rate and the structure of the as-grown nanotubes is presented using a C2H2/NH3 system and nickel as the catalyst. The activation energy for the growth rate was found to be 0.23 eV, much less than for thermal chemical Vapor Deposition (1.2–1.5 eV). This suggests growth occurs by surface diffusion of carbon on nickel. The result could allow direct growth of nanotubes onto low-temperature substrates like plastics, and facilitate the integration in sensitive nanoelectronic devices.
Stephan Hofmann - One of the best experts on this subject based on the ideXlab platform.
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catalytic chemical Vapor Deposition of single wall carbon nanotubes at low temperatures
Nano Letters, 2006Co-Authors: M Cantoro, Stephan Hofmann, Caterina Ducati, Simone Pisana, V Scardaci, A Parvez, Andrea Ferrari, A M Blackburn, Kaiyou Wang, J RobertsonAbstract:We report surface-bound growth of single-wall carbon nanotubes (SWNTs) at temperatures as low as 350 °C by catalytic chemical Vapor Deposition from undiluted C2H2. NH3 or H2 exposure critically facilitates the nanostructuring and activation of sub-nanometer Fe and Al/Fe/Al multilayer catalyst films prior to growth, enabling the SWNT nucleation at lower temperatures. We suggest that carbon nanotube growth is governed by the catalyst surface without the necessity of catalyst liquefaction.
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low temperature growth of carbon nanotubes by plasma enhanced chemical Vapor Deposition
Applied Physics Letters, 2003Co-Authors: Stephan Hofmann, Caterina Ducati, J Robertson, B KleinsorgeAbstract:Vertically aligned carbon nanotubes were grown at temperatures as low as 120 °C by plasma-enhanced chemical Vapor Deposition. A systematic study of the temperature dependence of the growth rate and the structure of the as-grown nanotubes is presented using a C2H2/NH3 system and nickel as the catalyst. The activation energy for the growth rate was found to be 0.23 eV, much less than for thermal chemical Vapor Deposition (1.2–1.5 eV). This suggests growth occurs by surface diffusion of carbon on nickel. The result could allow direct growth of nanotubes onto low-temperature substrates like plastics, and facilitate the integration in sensitive nanoelectronic devices.
R E I Schropp - One of the best experts on this subject based on the ideXlab platform.
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very thin and stable thin film silicon alloy triple junction solar cells by hot wire chemical Vapor Deposition
Applied Physics Letters, 2016Co-Authors: L W Veldhuizen, R E I SchroppAbstract:We present a silicon-based triple junction solar cell that requires a Deposition time of less than 15 min for all photoactive layers. As a low-bandgap material, we used thin layers of hydrogenated amorphous silicon germanium with lower band gap than commonly used, which is possible due to the application of hot wire chemical Vapor Deposition. The triple junction cell shows an initial energy conversion efficiency exceeding 10%, and with a relative performance stability within 6%, the cell shows a high tolerance to light-induced degradation. With these results, we help to demonstrate that hot wire chemical Vapor Deposition is a viable Deposition method for the fabrication of low-cost solar cells.
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growth process and properties of silicon nitride deposited by hot wire chemical Vapor Deposition
Journal of Applied Physics, 2003Co-Authors: Bernd Stannowski, J K Rath, R E I SchroppAbstract:Hot-wire chemical Vapor Deposition (HWCVD) is a promising technique for the Deposition of silicon nitride layers (a-SiNx:H) at low temperatures. In contrast to the commonly used plasma-enhanced chemical Vapor Deposition, no ion bombardment is present in HWCVD, which makes it particularly attractive for the Deposition of passivation layers on structures that are sensitive to the impact of energetic ions. We deposit hot-wire a-SiNx:H from a mixture of silane and ammonia at substrate temperatures in the range of 300–500 °C. Layers deposited with an ammonia/silane gas-flow ratio of R=30 are close to stoichiometry (N/Si=1.33) with a hydrogen content around 10 at. %. Such films have been implemented in hot-wire a-Si:H thin-film transistors. Deposition with R>30 did not result in an increase of the N content, but led to more porous films. Infrared spectroscopy revealed that moisture penetrates these layers and that oxygen is incorporated in the network under air exposure. Cross-sectional transmission electron mi...
Caterina Ducati - One of the best experts on this subject based on the ideXlab platform.
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catalytic chemical Vapor Deposition of single wall carbon nanotubes at low temperatures
Nano Letters, 2006Co-Authors: M Cantoro, Stephan Hofmann, Caterina Ducati, Simone Pisana, V Scardaci, A Parvez, Andrea Ferrari, A M Blackburn, Kaiyou Wang, J RobertsonAbstract:We report surface-bound growth of single-wall carbon nanotubes (SWNTs) at temperatures as low as 350 °C by catalytic chemical Vapor Deposition from undiluted C2H2. NH3 or H2 exposure critically facilitates the nanostructuring and activation of sub-nanometer Fe and Al/Fe/Al multilayer catalyst films prior to growth, enabling the SWNT nucleation at lower temperatures. We suggest that carbon nanotube growth is governed by the catalyst surface without the necessity of catalyst liquefaction.
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low temperature growth of carbon nanotubes by plasma enhanced chemical Vapor Deposition
Applied Physics Letters, 2003Co-Authors: Stephan Hofmann, Caterina Ducati, J Robertson, B KleinsorgeAbstract:Vertically aligned carbon nanotubes were grown at temperatures as low as 120 °C by plasma-enhanced chemical Vapor Deposition. A systematic study of the temperature dependence of the growth rate and the structure of the as-grown nanotubes is presented using a C2H2/NH3 system and nickel as the catalyst. The activation energy for the growth rate was found to be 0.23 eV, much less than for thermal chemical Vapor Deposition (1.2–1.5 eV). This suggests growth occurs by surface diffusion of carbon on nickel. The result could allow direct growth of nanotubes onto low-temperature substrates like plastics, and facilitate the integration in sensitive nanoelectronic devices.
Anne C. Dillon - One of the best experts on this subject based on the ideXlab platform.
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Continuous Hot Wire Chemical Vapor Deposition of High-Density Carbon Multiwall Nanotubes
Nano Letters, 2003Co-Authors: Anne C. Dillon, A. Harv Mahan, Jeffery L. Alleman, Kim M. Jones, Michael J. Heben, Philip A. Parilla, K. E. H. GilbertAbstract:Hot wire chemical Vapor Deposition (HWCVD) has been adapted to be a continuous growth process for high-density carbon multiwall nanotubes (MWNTs). MWNT growth is optimized in 1:5 CH4:Ar at 150 Torr with reactor temperatures of 400 and 550 °C for static and flowing gases, respectively. Ferrocene is employed to provide a gas-phase catalyst. Highly graphitic nanotubes can be continuously deposited with iron content as low as 15 wt % and carbon impurities below thermal gravimetric analysis detection limits. The MWNTs are simply purified to 99.5 wt % with minimal structural damage and with a 75 wt % yield. Carbon multiwall nanotubes (MWNTs) are promising for multiple applications including strong composite materials, field emission displays, and adsorbents for gas separation or storage. A continuous low-cost production method for easily purified MWNTs is therefore desired. MWNTs were discovered while Vaporizing carbon in an electric arc 1 and were then produced at higher yield by increasing the pressure of the helium gas atmosphere. 2 Chemical Vapor Deposition (CVD) techniques employing benzene pyrolosis, 3 and the decomposition of ethylene 4 and acetylene 5 on supported metal catalysts were also demonstrated as viable large-scale production methods. Recently, MWNTs have been grown on supported metal particles or films via CVD, 6-10 plasma enhanced CVD, 11-21 hot wire chemical Vapor Deposition (HWCVD), 22,23 and plasma enhanced HWCVD methods. 24,25
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Hot wire chemical Vapor Deposition of isolated carbon single-walled nanotubes
Applied Physics Letters, 2002Co-Authors: A. Harv Mahan, Jeffery L. Alleman, Kim M. Jones, Michael J. Heben, Philip A. Parilla, Anne C. DillonAbstract:Hot wire chemical Vapor Deposition (HWCVD) has been employed for the continuous generation of carbon single-walled nanotube (SWNT) materials. Interestingly, transmission electron microscopy analyses revealed only the presence of isolated SWNTs, rather than nanotubes existing in bundles. An analysis of the growth mechanism explaining the production of isolated SWNTs is provided. Also, the Raman radial breathing modes (RBMs) of the isolated HWCVD-generated nanotubes are compared to the RBMs of small bundles of nanotubes deposited by a conventional CVD technique having a similar diameter distribution.
