Control of nano-carbon synthesized in liquid phase under high magnetic field

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Carbon nanotubes have been commonly synthesized using a wide variety of chemical vapor deposition (CVD) methods, arc discharge and laser ablation techniques. These synthesis methods require a high synthesis temperature, at least 500℃. A low-temperature synthesis is important for an application of nanotubes and nanowires to practical devices. Since we have reported the room temperature nano-carbon synthesis by electrochemical techniques, high magnetic fields up to 12 Tesla are applied to electrochemical techniques for carbon nanotube synthesis. The deposits were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). An increase in the long carbon nanowires due to magnetic field was observed by TEM. In addition, high magnetic fields up to 12 Tesla are applied to thermal CVD for carbon nanotube synthesis. An increase in the onion-like nano-carbons and due to magnetic field was observed by TEM. Beside these synthesis methods, we have discovered another room temperature synthesis method of carbon nanotubes and carbon nanowires. The new room temperature synthesis has been achieved by a supersonic irradiation into a liquid phase of organic solution with a metal catalyst and metal Na. The temperature increase during the deposition is negligible, because of by a few degrees at most. This low temperature synthesis method has a great advantage to develop carbon-based new materials. In addition, the apparatus used in the present study is simple and is not expensive. Therefore, this technique will make it possible to develop other nanosized new materials.