Low-temperature electron transport spectroscopy was used to evaluate defects in individual single-walled carbon nanotube devices assembled via dielectrophoresis from a surfactant-free solution. At 4.2K, the majority of the devices showed periodic and well-defined Coulomb diamonds near to zero gate voltage corresponding to transport through a single quantum dot. At higher gate voltages, a beating behavior was observed due to small potential fluctuations induced by the substrate. The Coulomb diamonds were further modeled by using a single electron transistor simulator. The present study suggested that single-walled carbon nanotubes derived here from stable solutions were free from hard defects and were relatively clean.

Evaluating Defects in Solution-Processed Carbon Nanotube Devices via Low-Temperature Transport Spectroscopy. P.Stokes, S.I.Khondaker: ACS Nano, 2010, 4[5], 2659-66