Defect Evolution of Ion-Exposed Single-Wall Carbon Nanotubes

The electronic properties
of carbon nanotubes depend on several
factors such as diameter, chirality, and defects. Defects such as
vacancies can drastically modify the electronic properties of these
nanostructures. The introduction of defects by irradiation processes
can not only lead to interesting defective nanomaterials but also
tailor its intrinsic properties for specific electronic applications.
The ability to accurately identify and quantify defects in carbon
nanotubes is of major importance for their incorporation into electronic
devices. We report on a newly developed quantitative method which
combines a known fluence or pulse of ions from a focused beam source
with Raman spectroscopy for characterization of defects enabling the
detection of systematic variations in defect concentration emerging
at 0.5% from different single-wall carbon nanotube (SWCNT) types,
semiconducting and metallic. It was also demonstrated that this result
is independent from the selected ion species and its energy for thin
films, which makes both types of ions suitable for these types of
manipulations and characterizations. In this paper, the methods described
and exploited can be performed without unique experimental setup or
sample preparation and thus enabling in situ accurate characterization
of SWCNTs, devices, and other targeted applications.