Current on/off ratio enhancement of field effect transistors with bundled carbon nanotubes

This work examines the enhancement of current on/off ratio in field effect transistor devices with bundled single-walled carbon nanotubes (CNTs) by incorporating a substrate etching step before the electrical cutting for metallic CNT elimination. The etching step prevents the damaging of the semiconducting CNTs while burning off the metallic ones by electrical current. By further incorporating a repeated gate voltage sweeping step, devices with low $Ioff$ (less than 2 nA) and high $Ion/Ioff$⁠, which is one to five orders of magnitude larger than before etching/cutting combination process, can be obtained.