High magnetic field reveals the nature of excitons in a single GaAs/AlAs core/shell nanowire

TL;DR

This study uses high magnetic fields to analyze excitons in individual GaAs/AlAs nanowires, revealing high optical quality and strong room-temperature emission suitable for optoelectronic devices.

Contribution

It demonstrates that GaAs/AlAs nanowires have optical qualities comparable to high-quality epitaxial layers and reveals exciton behavior under magnetic fields.

Findings

Detection of exciton lines associated with defect pairs.

Observation of strong free exciton emission at room temperature.

Nanowires exhibit optical quality comparable to molecular beam epitaxy layers.

Abstract

Magneto-photoluminescence measurements of individual zinc-blende GaAs/AlAs core/shell nanowires are reported. At low temperature a strong emission line at 1.507 eV is observed under low power (nW) excitation. Measurements performed in high magnetic field allowed us to detect in this emission several lines associated with excitons bound to defect pairs. Such lines were observed before in epitaxial GaAs of very high quality, as reported by Kunzel and Ploog. This demonstrates that the optical quality of our GaAs/AlAs core/shell nanowires is comparable to the best GaAs layers grown by molecular beam epitaxy. Moreover, strong free exciton emission is observed even at room temperature. The bright optical emission of our nanowires in room temperature should open the way for numerous optoelectronic device applications.