Tunable bandgaps and excitons in doped semiconducting carbon nanotubes made possible by acoustic plasmons

TL;DR

This paper demonstrates that doping in semiconducting carbon nanotubes can significantly tune their bandgaps and exciton energies through a novel acoustic plasmon mechanism, enabling broad and controllable optical property adjustments.

Contribution

It introduces a new mechanism involving acoustic plasmons that allows for tunable electronic and optical properties in doped carbon nanotubes, unlike traditional higher-dimensional systems.

Findings

Doping reduces bandgaps and exciton binding energies in carbon nanotubes.

Tuning of electronic properties is achieved over a broad energy range.

Acoustic plasmons mediate strong dynamical screening effects.

Abstract

Doping of semiconductors is essential in modern electronic and photonic devices. While doping is well understood in bulk semiconductors, the advent of carbon nanotubes and nanowires for nanoelectronic and nanophotonic applications raises some key questions about the role and impact of doping at low dimensionality. Here we show that for semiconducting carbon nanotubes, bandgaps and exciton binding energies can be dramatically reduced upon experimentally relevant doping, and can be tuned gradually over a broad range of energies in contrast to higher dimensional systems. The later feature is made possible by a novel mechanism involving strong dynamical screening effects mediated by acoustic plasmons.