UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2007 Meeting


Section: Quantum Mechanics, Statistical Physics, Optics, Spectroscopy, Plasma and Lasers


Title:
Two dimensional carbon nanostructures deposited by radiofrequency Ar plasma beam injected with acetylene/hydrogen mixtures


Authors:
S. Vizireanu(1), D. Stoica(1), B. Mitu(1), L. Nistor(2), G. Dinescu(1)


Affiliation:
1 National Institute for Laser, Plasma and Radiation Physics, Magurele, PO Box MG-36, Bucharest, 077125 Romania

2 National Institute for Materials Physics, Magurele, Bucharest, 077125 Romania


E-mail


Keywords:
carbon nanowalls, expanding radiofrequency plasma, radiofrequency plasma enhanced vapor deposition


Abstract:
Two dimensional carbon nano-materials, known as carbon nanowalls, are among the newest carbon nanostructures. These structures are attractive and extremely interesting due to their reduced dimensionality (2D), open boundaries, sharp edges and their high surface-to-volume ratio. The usual techniques of synthesis of these nanostructures are Radiofrequency Plasma Enhanced CVD and Microwave Plasma Enhanced CVD. We report in this contribution the growth of carbon nanowalls in a plasma beam sustained by an expanding argon radiofrequency discharge and injected with a small amount of acetylene in presence of hydrogen (remote deposition). The investigated parameters in the formation of nanostructured carbon were the mass flow rates and ratios of gases (argon, hydrogen and acetylene), substrate temperature, substrate position, and the radiofrequency power. The deposition environment was studied by Optical Emission Spectroscopy. The most important radicals involved in the plasma beam have been identified and their dependence on the experimental conditions was obtained. The presence of carbon nanowalls was proven by several techniques Scanning and Transmission Electron Microscopy, Raman Spectroscopy, Electron and X-ray Diffraction. Various materials morphologies can be obtained in the plasma beam as granular carbon, carbon nanofibers, carbon nanotubes, carbon nanowalls. The nanostructured carbon material with 2D morphology is obtained in a specific range of parameter values. The most important elements, which lead to preferential growth of carbon nanowalls, against of other forms of nanostructured carbon are the presence of hydrogen and catalyst and a suitable ratio of gases.