Carbon Nanotube Growth Studies Using an Atmospheric, Microplasma Reactor

This paper reports chemical vapor deposition (CVD) of carbon nanotube arrays at substrate temperatures lower than 100degC and growth rates greater than 50 mum/h using atmospheric plasma discharges inside microcapillary reactors. Thermal CVD using the same reactor required temperatures in excess of 900degC. At temperatures greater than 1100degC, the thermal CVD yielded an unusual, diverging conical morphology. The microreactor studies suggest no new micrometer scale effects for thermal CVD. On the other hand, the microplasma discharges show beneficial effects on nanotube growth due to high plasma densities achieved at submillimeter reactor dimensions. The results suggest that the nanotube growth rates are proportional to plasma radical density.