Fabrication of tunnel barriers and single electron transistors in suspended multi-wall carbon nanotubes

Abstract

Fabrication processes have been developed to form the tunnel barriers in the suspended multi-wall carbon nanotubes (MWCNTs). Individual MWCNTs are positioned under the optical microscope to bridge them between the two metal electrodes. The tunnel barrier is formed by irradiating them with focused Ga ion beam (FIB), and its characteristics are evaluated with the resistance increase by the irradiation and the barrier height. It is found that those values depend not only on the dose of the Ga ions, but also on a diameter of the MWCNT. The single electron transistors (SETs) are fabricated by forming the double barriers in the suspended MWCNT. We find some devices show regular and stable SET behaviours.