On the low-temperature synthesis of SWCNTs by thermal CVD

We present some experimental results obtained on the study of catalytic activity of iron, for the growth of carbon nanotubes (CNTs) at moderate temperature. The catalysts consist of a 0.5 nm thick layer of iron deposited on Si (1 0 0) substrate. The synthesis of CNTs was studied between 400 and 800 °C using methane or ethylene as carbon source, in order to distinguish the thermodynamic limit of the carbohydrate decomposition from the limit of the process of growth of nanotubes. We show that isolated single-walled carbon nanotubes (SWCNTs) can be obtained at 450 °C using ethylene in a pure thermal process.