Intra- and intertube tunneling transport in ropes of single-walled carbon nanotubes

The authors report on intra- and intertube tunneling induced current oscillations in an individual rope of single-walled carbon nanotubes. Defects within single tubes and tube-tube contacts provide tunneling barriers of different transparencies and heights, respectively, and the formation of quantum dots in between. As a function of the bias voltage, the authors observe a transition from an intratube to an intertube tunneling dominated transport. The samples were fabricated on prepatterned silicon substrates employing surface acoustic wave induced streaming leading to an alignment of the ropes with respect to the contacts.