UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2011 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Investigation of the relationship between plasma characteristics and the properties of carbon nanowalls synthesized by PECVD


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


Affiliation:
National Institute for Laser, Plasma and Radiation Physics, Magurele, 077125, Romania (1)

National Institute for Materials Physics, Magurele-Bucharest, 077125, Romania (1)


E-mail
daniel.stoica@infim.ro


Keywords:
argon/hydrogen/acetylene plasma, radiofrequency plasma jet, carbon nanowalls


Abstract:
We have previously reported [1] a method for synthesis in a low pressure plasma beam of various carbon nanostructures, such as carbon nanotubes, nanofibers or carbon nanowalls layers. The structure and morphology of the material is strongly dependent on the experimental conditions. In this contribution we present results concerning the characteristics of the plasma beam used for the carbon nanowalls synthesis, and also show how the structure and morphology depend on these characteristics. Such as we have noticed that the Ar/H2/C2H2 ratio, substrate position, pressure and injected power are the most important plasma parameters that lead to a certain behaviour of the materials [2]. The diagnostic techniques that have been used were optical emission spectroscopy, Langmuir probe measurements and mass spectrometry. The investigations were made along the plasma beam axis, where deposition takes place. The most important signatures in the emission spectrum are coming from C2, CH, CN, OH molecular radicals and from the H and Ar atoms. The electron density, temperature, energy distribution and plasma potential have resulted from the electrical probe investigation. Other species, as neutrals and ions, were studied by mass spectrometry. The material properties were investigated by means of SEM, TEM, SAED and Raman spectroscopy. Carbon nanowalls with small thickness and large surface area are obtained in optimum conditions. The role of plasma conditions in obtaining high quality carbon nanowalls is discussed. References: [1] S. Vizireanu, L. Nistor, M. Haupt, V. Katzenmaier, C. Oehr, G. Dinescu, Plasma Processes and Polymers, Vol. 5, Issue 3, 263-268, 2008 [2] S. Vizireanu, S.D. Stoica, C. Luculescu , L.C. Nistor, B. Mitu, G. Dinescu, Plasma Sources Science and Technology, vol 19, 034016, 2010