Scanning Tunneling Spectroscopy of Suspended Single-Wall Carbon Nanotubes

TL;DR

This study uses low-temperature scanning tunneling microscopy to investigate the electronic properties of suspended single-wall carbon nanotubes, revealing atomic resolution imaging and Coulomb blockade phenomena.

Contribution

It demonstrates atomic resolution imaging and spatially resolved spectroscopy on suspended nanotubes, highlighting Coulomb-staircase behavior and tip-tube capacitance effects.

Findings

Atomic resolution on freestanding nanotubes

Observation of Coulomb-staircase in spectroscopy

Tip position affects Coulomb blockade peak spacing

Abstract

We have performed low-temperature STM measurements on single-wall carbon nanotubes that are freely suspended over a trench. The nanotubes were grown by CVD on a Pt substrate with predefined trenches etched into it. Atomic resolution was obtained on the freestanding portions of the nanotubes. Spatially resolved spectroscopy on the suspended portion of both metallic and semiconducting nanotubes was also achieved, showing a Coulomb-staircase behavior superimposed on the local density of states. The spacing of the Coulomb blockade peaks changed with tip position reflecting a changing tip-tube capacitance.