Gate-voltage induced trions in suspended carbon nanotubes

TL;DR

This study demonstrates gate-voltage induced trion emission in suspended carbon nanotubes, revealing size-dependent energy separation and larger binding energies due to reduced dielectric screening.

Contribution

It provides the first observation of electrostatically induced trions in suspended nanotubes and links their properties to nanotube diameter and dielectric environment.

Findings

Trion emission appears at specific gate voltages coinciding with exciton quenching.

Energy separation between exciton and trion peaks decreases with increasing nanotube diameter.

Suspended nanotubes exhibit larger trion binding energies compared to surfactant-wrapped ones.

Abstract

We observe trion emission from suspended carbon nanotubes where carriers are introduced electrostatically using field-effect transistor structures. The trion peak emerges below the $E_{11}$ emission energy at gate voltages that coincide with the onset of bright exciton quenching. By investigating nanotubes with various chiralities, we verify that the energy separation between the bright exciton peak and the trion peak becomes smaller for larger diameter tubes. Trion binding energies that are significantly larger compared to surfactant-wrapped carbon nanotubes are obtained, and the difference is attributed to the reduced dielectric screening in suspended tubes.