Identifying and counting point defects in carbon nanotubes
简介:The prevailing conception of carbon nanotubes and
particularly single-walled carbon nanotubes (SWNTs)
continues to be one of perfectly crystalline wires. Here,
we demonstrate a selective electrochemical method that
l简介:The prevailing conception of carbon nanotubes and
particularly single-walled carbon nanotubes (SWNTs)
continues to be one of perfectly crystalline wires. Here,
we demonstrate a selective electrochemical method that
labels point defects and makes them easily visible for
quantitative analysis. High-quality SWNTs are confirmed to
contain one defect per 4 μm on average, with a distribution
weighted towards areas of SWNT curvature. Although
this defect density compares favourably to high-quality,
silicon single-crystals, the presence of a single defect can
have tremendous electronic effects in one-dimensional
conductors such as SWNTs.We demonstrate a one-to-one
correspondence between chemically active point defects
and sites of local electronic sensitivity in SWNT circuits,
confirming the expectation that individual defects may
be critical to understanding and controlling variability,
noise and chemical sensitivity in SWNT electronic devices.
By varying the SWNT synthesis technique, we further
show that the defect spacing can be varied over orders
of magnitude. The ability to detect and analyse point
defects, especially at very low concentrations, indicates
the promise of this technique for quantitative process
analysis, especially in nanoelectronics development.详细>