Local density of states and electronic transport properties of homotype SWCNTs bundles

Ribbons constituted by homotype bundles, i.e. made preferentially by carbon nanotubes having the same diameter have been analyzed. In particular the structural, morphological, and electronic properties have been evaluated. The measurements of the basic transport properties have allowed to fit the electronic behaviour of ribbons formed by the macroscopic aggregation of such homotype bundles to a model based on the coupling tunnelling conductance of highly aligned nanotube systems. The parallel arrangement of nanotubes with the same chirality in bundles and the resulting peculiar intertube interactions suggest a mean of controlling the LDOS by configuring different architectures. The dependence of the ribbon conductance on the temperature has been rationalized considering the presence, in a given ribbon, of both metal-like and semiconducting homotype bundles. In addition, photoconductivity properties of aggregated single-walled carbon nanotubes are also studied.