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11 results on '"Rupesinghe, Nalin L"'

2. The Role of Plasma in Plasma Enhanced Chemical Vapour Deposition of Nanostructure Growth

Author

Hash, David B, Meyyappan, M, Teo, Kenneth B. K, Lacerda, Rodrigo G, and Rupesinghe, Nalin L

Subjects
Plasma Physics
Abstract

Chemical vapour deposition (CVD) has become the preferred process for high yield growth of carbon nanotubes and nanofibres because of its ability to pattern growth through lithographic positioning of transition metal catalysts on substrates. Many potential applications of nanotubes such as field emitters [1] require not only patterned growth but also vertical alignment. Some degree of ali,ment in thermal CVD processes can be obtained when carbon nanotubes are grown closely together as a result of van der Waals interactions. The ali,onment however is marginal, and the van der Waals prerequisite makes growth of freestanding nanofibres with thermal CVD unrealizable. The application of electric fields as a means of ali,onment has been shown to overcome this limitation [2-5], and highly aligned nanostructures can be grown if electric fields on the order of 0.5 V/microns are employed. Plasma enhanced CVD in various configurations including dc, rf, microwave, inductive and electron cyclotron resonance has been pursued as a means of enabling alignment in the CVD process. However, the sheath fields for the non-dc sources are in general not sufficient for a high degree of ali,pment and an additional dc bias is usually applied to the growth substrate. This begs the question as to the actual role of the plasma. It is clear that the plasma itself is not required for aligned growth as references [3] and [4] employed fields through small applied voltages (3-20 V) across very small electrode spacings (10-100 microns) and thus avoided striking a discharge.

Published
2004

4. Vertically aligned CNT growth on a microfabricated silicon heater with integrated temperature control—determination of the activation energy from a continuous thermal gradient

Author

Engstrøm, Daniel Southcott, Rupesinghe, Nalin L, Teo, Kenneth B K, Milne, William I, Bøggild, Peter, Engstrøm, Daniel Southcott, Rupesinghe, Nalin L, Teo, Kenneth B K, Milne, William I, and Bøggild, Peter

Abstract

Silicon microheaters for local growth of a vertically aligned carbon nanotube (VACNT) were fabricated. The microheaters had a four-point-probe structure that measured the silicon conductivity variations in the heated region which is a measure of the temperature. Through FEM simulations the temperature was determined on the entire microheater structure, and the simulated temperatures were verified by micro-Raman spectroscopy. The microheaters provided a temperature gradient along which VACNTs were grown at 575–800 °C simultaneously. The VACNT growth activation energy was determined to 0.86 eV from the VACNT growth rate variation along the microheater's temperature gradient.

Published
2011

5. Growth of continuous graphene by open roll-to-roll chemical vapor deposition.

Author

Guofang Zhong, Xingyi Wu, D'Arsie, Lorenzo, Teo, Kenneth B. K., Rupesinghe, Nalin L., Jouvray, Alex, and Robertson, John

Subjects
GRAPHENE, CHEMICAL vapor deposition, MONOMOLECULAR films, CHEMICAL reactors, TEMPERATURE
Abstract

We demonstrate the growth of high-quality, continuous monolayer graphene on Cu foils using an open roll-to-roll (R2R) chemical vapor deposition (CVD) reactor with both static and moving foil growth conditions. N2 instead of Ar was used as carrier gas to reduce process cost, and the concentrations of H2 and CH4 reactants were kept below the lower explosive limit to ensure process safety for reactor ends open to ambient. The carrier mobility of graphene deposited at a Cu foil winding speed of 5 mm/min was 5270-6040 cm2V-1 s-1 at room temperature (on 50 μm ×50 μm Hall devices). These results will enable the inline integration of graphene CVD for industrial R2R production. [ABSTRACT FROM AUTHOR]

Published
2016
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11. The Significance of Plasma Heating in Carbon Nanotube and Nanofiber Growth

Author

Teo, Kenneth B. K., primary, Hash, David B., additional, Lacerda, Rodrigo G., additional, Rupesinghe, Nalin L., additional, Bell, Martin S., additional, Dalal, Sharvari H., additional, Bose, Deepak, additional, Govindan, T. R., additional, Cruden, Brett A., additional, Chhowalla, Manish, additional, Amaratunga, Gehan A. J., additional, Meyyappan, M., additional, and Milne, William I., additional

Published
2004
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