UV Emission from GaN Wires with m-Plane Core–Shell GaN/AlGaN Multiple Quantum Wells
- 7 September 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Applied Materials & Interfaces
- Vol. 12 (39), 44007-44016
- https://doi.org/10.1021/acsami.0c08765
Abstract
The present work reports high quality non-polar GaN/Al0.6Ga0.4N multiple quantum wells (MQWs) grown in core-shell geometry by metalorganic vapor phase epitaxy on the m-plane sidewalls of c ̅-oriented hexagonal GaN wires. Optical and structural studies reveal UV emission originating from the core-shell GaN/AlGaN MQWs. Tuning the m-plane GaN QW thickness from 4.3 to 0.7 nm leads to a shift of the emission from 347 to 292 nm, consistent with Schrödinger-Poisson calculations. The evolution of the luminescence with temperature displays signs of strong localization, especially for samples with thinner GaN QWs and no evidence of quantum confined Stark effect, as expected for non-polar m-plane surfaces. The internal quantum efficiency derived from the photoluminescence intensity ratio at low and room temperature is maximum (~7.3 %) for 2.6 nm-thick quantum wells, emitting at 325 nm and shows a large drop for thicker QWs. An extensive study of the PL quenching with temperature is presented. Two non-radiative recombination paths are activated at different temperatures. The low temperature path is found to be intrinsic to the heterostructure, whereas the process that dominates at high temperature depends on the QW thickness and is strongly enhanced for QWs larger than 2.6 nm, causing a drop of the internal quantum efficiency.Funding Information
- Irish Research Council
- Teagasc
- Minist?re de l'Enseignement Sup?rieur et de la Recherche Scientifique
- Universit? Grenoble Alpes (15-IDEX-0002)
- Minist?re des Affaires Etrang?res et du D?veloppement International
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