The effect of helium gas pressure on the formation and yield of nanotubes in arc discharge

Abstract
The effect of helium gas pressure on the formation of nanotubes in arc-discharge cathodic deposits was investigated by transmission electron microscopy, thermal gravimetric analysis and differential thermal analysis. Compared with the same thermal analysis of and graphite, the results show that the ratio of the nanotubes to nanoparticles in deposits increases with increasing helium gas pressure ranging from 80 to 700 Torr. These results can be regarded as an approach for controlling the ratio of the nanotubes to nanoparticles by controlling helium atmospheric conditions.