Nanotubes and nanowires: the effect of impurities and defects on their electronic properties

In recent years, our laboratory has conducted extensive research studies on nanoscale systems. We give here a brief overview of these activities, and also present some previously unpublished results on the influence of impurities and defects on the electronic properties of carbon nanotubes and metallic nanowires. In the case of carbon nanotubes, we show that the presence of structural defects such as strong bends can lead to the presence of electronic states in the gap (for semiconducting nanotubes), which we correlate with recent scanning tunnel microscopy and spectroscopy measurements. In the case of metallic nanowires, we discuss the effect of the presence of carbon impurities, which have been suggested to be present in atomic gold nanowires, on their electronic transport properties. In particular, we show that the conductance in the presence of impurities deviates considerably from that of the pure gold atomic wires.