Minimal bundling of single-walled carbon nanotubes comprising vertically aligned films

A freestanding film of vertically aligned single-walled carbon nanotubes (VA-SWNTs) synthesized by the alcohol catalytic chemical vapor deposition (ACCVD) method was observed directly by transmission electron microscopy (TEM). These observations revealed that the film is comprised primarily of small SWNT bundles, typically containing 3-8 SWNTs. The lack of significant bundling is supported by electron diffraction spectra, in which no bundle peak is observed, and by electron energy-loss spectroscopy (EELS), which shows minimal dielectric screening. This indicates the electrical properties of the VA-SWNT film are dominated by the one-dimensional nature of SWNTs, rather than behaving as a bulk material.