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Identification of nonradiative recombination channels in Ga0.2Al0.8N-AlN wells with deep ultraviolet emission at 215 nm

Alexandra Ibanez1, Sunanda Mitra2, Sylvia Hagedorn3, Wilfried Desrat1, Pierre Valvin1, Guillaume Cassabois1,4, Julien Brault2, and Bernard Gil1,*

  • *Contact author: bernard.gil@umontpellier.fr
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APS Open Sci. 1, 000210 – Published 9 November, 2026

DOI: https://doi.org/10.1103/3yzl-jn7v

Abstract

The optical efficiency of deep-ultraviolet nitride-based heterostructures emitting at wavelengths around 215 nm remains severely limited by thermally activated nonradiative recombination processes. In this article, we investigate the optical properties of high-quality Ga0.2Al0.8N multiple quantum wells grown by molecular beam epitaxy on AlN templates fabricated either by metal-organic chemical vapor deposition or by molecular beam epitaxy. The temperature-dependent photoluminescence measurements performed in the 10–300 K range reveal that the thermal quenching of the photoluminescence emission is governed by three distinct activation processes common to all the sample series. The first nonradiative recombination channel, characterized by an activation energy in the 4–8 meV range, is extrinsic in origin and is associated with impurities as well as with the density of structural defects within the crystal. The second process, with an activation energy of 70 meV, is intrinsic in nature and is related to the thermal dissociation of the free exciton. A third thermally activated process, also intrinsic, exhibits an activation energy of approximately 130 meV and is assigned to the thermal escape of electrons and/or holes from the active region of the multiple quantum wells, leading to a further reduction in optical efficiency at elevated temperatures.

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APS Open Sci. 1, 000210– Published 9 November, 2026
Vol. 1
  • Received 31 May 2026
  • Accepted 29 September 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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