Direct growth of carbon nanotube junctions by a two-step chemical vapor deposition

A simple two-step chemical vapor deposition (CVD) strategy was designed for the direct growth of all-carbon nanojunctions constituted by jointed carbon nanotubes. In the process, Fe–Mo nanoparticles were used as the catalysts, while C2H2 and CH4 were used as the feeding gas in the first and second CVD steps, respectively. By changing temperature and switching carbon source gases in the CVD process, various nanojunctions composed of single-walled and multi-walled carbon nanotubes were prepared. These all-carbon nanojunctions are expected to show special mechanical and electrical properties for the potential applications as the field-emission probes, scanning probe microscope tips and field-effect transistors.