Electroluminescence from chirality-sorted (9,7)-semiconducting carbon nanotube devices

TL;DR

This study demonstrates that electroluminescence from (9,7) semiconducting carbon nanotubes is determined by their chirality, with devices showing a specific emission wavelength linked to their chiral index, and explores their optical properties.

Contribution

First demonstration of electroluminescence in chirality-sorted (9,7) carbon nanotube devices with spectral features linked to their chiral index.

Findings

Electroluminescence wavelength at 825 nm for (9,7) nanotubes.

Emission peak corresponds to excitonic E22 transition.

EL peak width linearly depends on electrical current.

Abstract

We have measured the electroluminescence and photoluminescence of (9,7) semiconducting carbon nanotube devices and demonstrate that the electroluminescence wavelength is determined by the nanotube's chiral index (n,m). The devices were fabricated on Si3N4 membranes by dielectrophoretic assembly of tubes from monochiral dispersion. Electrically driven (9,7) devices exhibit a single Lorentzian shaped emission peak at 825 nm in the visible part of the spectrum. The emission could be assigned to the excitonic E22 interband transition by comparison of the electroluminescence spectra with corresponding photoluminescence excitation maps. We show a linear dependence of the EL peak width on the electrical current, and provide evidence for the inertness of Si3N4 surfaces with respect to the nanotubes optical properties.