Investigation of H2/CH4 plasma composition in nonmagnetic growth of single-walled carbon nanotubes by plasma chemical vapor deposition

In situ plasma analysis was performed during the single-walled carbon nanotubes (swnts) growth from nonmagneticcatalysts with plasma chemical vapor deposition (pcvd). the system based on optical emission spectroscopy(oes) was dedicated for in situ diagnostics of pcvd processes. the swnts growth were performed for avarious h2 flow rates with 50w of an radio frequency (rf) power. nonmagnetic metal particles were found to havecatalytic activity for the growth of swnts under a specific plasma condition. the plasma analysis revealed that theintensities of há and ch radicals remarkably increased and decreased by increasing the h2 flow rate, respectively.based on the comparison between the growth condition of swnts and results of plasma analysis, it was found thatthe intensity ratio of ch/há shows fairly similar tendency to the yield of swnts as a function of h2 flow rate, i.e.swnts could be grown from nonmagnetic catalysts only when ch/há is high. this indicates that the intensity ratioof ch/há could be useful to optimize the growth condition of swnts with au catalyst.