In situ observations of carbon nanotube formation using environmental transmission electron microscopy

Environmental transmission electron microscope is used for in situ observations of the growth mechanism and reaction conditions of carbon nanotubes. Chemical vapor deposition was performed by flowing propylene or acetylene gas (precursor) over Ni or Co catalyst heated to 450 °C and 700 °C. We are reporting the in situ observations of the growth process of carbon nanotubes. Multi-wall nanotubes formed at temperatures as low as 450 °C while only single-wall carbon nanotubes formed at higher temperatures (700 °C and above). At lower temperatures, a cubic phase was also observed to form on the walls of the multi-wall carbon nanotubes.