Fabrication of single electron transistors in multi-wall carbon nanotubes using Ar beam irradiation

摘要

The Ar beam with an acceleration voltage of 300 V has been irradiated to multi-wall carbon nanotubes (MWNTs) through a narrow opening of the resist, in order to form a tunnel barrier. The tunnel resistance could be set by appropriate dose, in the range greater than h/e~2, and single electron transistors (SETs) have been fabricated with two tunnel barriers in series. Electrical transport measurements have been carried out at 2.6 K. Most of the samples have shown periodic Coulomb diamonds, suggesting the formation of a single quantum dot with a maximum Coulomb gap ranging from 5 to 26 meV. In a few samples, there was still a finite Coulomb gap at the gate voltages where two adjacent diamonds meet, suggesting an unexpected multi-barrier formation. The present technique may be useful for the fabrication of more complicated quantum dot-based nanodevices in carbon nanotubes.