Electrical transport measurements of nanotubes with known (n, m) indices

Because subtle changes in physical structure (chirality) can cause the electronic structure of carbon nano-tubes to vary from metallic to semiconducting, the goal of fully controlled nanotube device fabrication has proved elusive. Using a mechanical transfer technique in parallel with optical characterization, we have achieved the goal of placing 'the nanotube we want, where we want it'. Long nanotubes are grown by CVD across a slit etched through a Si wafer and then examined by Rayleigh scattering. By combining this technique with structural characterization by electron diffraction, we are able to map each spectrum to a unique (n, m) structure. After structural characterization, a chosen nanotube can be transferred to a substrate in the desired location, and devices fabricated using standard e-beam lithography techniques. We have fabricated a number of devices in this manner and are beginning to fully explore the detailed relationship between structure and transport. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.