EFFECT OF AMMONIA PLASMA TREATMENT ON THE NUCLEATION
PROCESS OF CARBON NANOMATERIALS GROWN VIA MICROWAVE
EXCITED SURFACE-WAVE PLASMA CVD
R.V. Bekarevich1, A.V. Rogachev2, M. Nagatsu1
1Shizuoka
2Francysk
University, Hamamatsu, Japan
Skaryna Homel State University, Homel, Belarus
Carbon nanotubes (CNTs), graphene and other carbon nanomaterials (CNMs) are the
subject of a strong scientific interest because of their unique honeycomb structure provides many
unusual properties [1]. Many researchers devote their studies to searching of the potential
applications of CNMs in different fields of human life: from textiles and concretes to molecular
electronics and cancer therapy. However existing methods of CNMs synthesis require high
temperature of the substrates what does not allow to use all type of the substrates and realize all
variety of the CNMs applications respectively. To solve this problem it is necessary to develop
large-scale low-temperature of the CNMs synthesis.
Our group have already demonstrated a possibility to grow the CNTs and few-layered
graphene sheets onto polyimide substrate by microwave-excited surface-wave plasma CVD
method at relatively low-temperature of 250 °C using graphene-encapsulated Ni nanoparticles
(GNN) as catalyst [2].
The important role of ammonia plasma pretreatment in the process of CNMs synthesis has
been shown in present research. Here we focused on the analysis of the initial stages of the
CNMs nucleation by investigation of the first step of the proposed process when only ammonia
plasma has been applied to activate the catalytic nanoparticles. Substrates covered by GNN have
been treated in the same experimental setup which was described earlier [2, 3]. In this research
surface-wave plasma has been produced in the ammonia atmosphere at working pressure 20 Pa.
Gas flow rate of NH3 has been fixed at 100 sccm, the substrate stage was biased negatively by a
pulsed squared wave with amplitude varied within –50 ~ –100 V at a frequency of 500 Hz.
The result of this treatment was not only etching of graphene layers surrounded GNN. It
was possible to observe new onion-like carbon structures grown on the surface of GNN without
applying of carbon source gas. The cause of such morphology changing can be the carbon
recombination processes lead to formation of new CNMs.
More details of this experimental study will be presented at the conference.
Acknowledgments: This work was supported in part by a Grant-in-Aid for Scientific Research (Grant
No. 2110010) from the Japan Society for the Promotion of Science (JSPS).
References:
[1] M. Endo, T. Hayashi, Y.A. Kim et al., Philos. T. R. Soc. A. 362 (2004), 2223-2238.
[2] R. V. Bekarevich, S. Miura, A. Ogino et al., Low-Temperature Synthesis of Carbon Nanotubes and
Graphene Sheets Using Microwave Plasma. Proceedings of: Microwave Discharges: Fundamentals and
Applications, (10–14 September 2012, Zvenigorod, Russia), pp. 197–205.
[3] R. V. Bekarevich, S. Miura, A. Ogino et al., J. Phys. Conf. Ser. 417 (2013), 012042.