Coupled study by TEM/EELS and STM/STS of electronic properties of C- and CNx-nanotubes

TL;DR

This study combines TEM/EELS and STM/STS techniques to investigate the electronic properties of carbon and nitrogen-doped nanotubes, focusing on their bandgap tuning, molecular orbitals, and effects of doping.

Contribution

It provides a comprehensive experimental analysis of the electronic structure and doping effects in nanotubes using multiple microscopy and spectroscopy methods.

Findings

Visualization of molecular orbitals in nanotubes

Insights into the role of many-body interactions on bandgaps

Effects of nitrogen doping on electronic properties

Abstract

Carbon nanotubes are the focus of considerable research efforts due to their fascinating physical properties. They provide an excellent model system for the study of one dimensional materials and molecular electronics. The chirality of nanotubes can lead to very different electronic behaviours, either metallic or semiconducting. Their electronic spectrum consists of a series of Van Hove singularities defining a bandgap for semiconducting tubes and molecular orbitals at the corresponding energies. A promising way to tune the nanotubes electronic properties for future applications is to use doping by heteroatoms. Here we report on experimental investigation of the role of many-body interactions in nanotube bandgaps, the visualization in direct space of the molecular orbitals of nanotubes and the properties of nitrogen doped nanotubes using scanning tunneling microscopy and transmission electron microscopy as well as electron energy loss spectroscopy.