Impact of oxide substrate on electrical and optical properties of carbon nanotube devices

We have studied suspended nanotube devices to investigate directly the impact of oxide substrate on the properties of nanotubes. The 1/f noise amplitude is reduced by about one order of magnitude when the nanotube is suspended, suggesting that the 1/f noise is dominated by the trapped charges in the oxide. We have also utilized the enhanced Raman signal intensity in suspended nanotubes to correlate electrical transport properties with Raman spectroscopy on the same individual nanotube, yielding close agreement in the tube diameter determined from both types of experiments