Mapping of functionalized regions on carbon nanotubes by scanning tunneling microscopy

TL;DR

This paper demonstrates a method to reliably map functionalized regions on carbon nanotubes using STM by embedding them in a graphene-nanotube composite, enabling atomic-scale, energy-resolved surface analysis.

Contribution

The study introduces a novel sample preparation technique that overcomes stability issues, allowing detailed STM mapping of functionalized carbon nanotubes at atomic resolution.

Findings

Identified charge transfer and doping levels on nanotubes.

Mapped defect creation and functionalization dependence on crystallography.

Enabled energy-resolved conductance measurements on functionalized nanotubes.

Abstract

Scanning tunneling microscopy (STM) gives us the opportunity to map the surface of functionalized carbon nanotubes in an energy resolved manner and with atomic precision. But this potential is largely untapped, mainly due to sample stability issues which inhibit reliable measurements. Here we present a simple and straightforward solution that makes away with this difficulty, by incorporating the functionalized multiwalled carbon nanotubes (MWCNT) into a few layer graphene - nanotube composite. This enabled us to measure energy resolved tunneling conductance maps on the nanotubes, which shed light on the level of doping, charge transfer between tube and functional groups and the dependence of defect creation or functionalization on crystallographic orientation.