Aluminum-gallium-nitride alloys (Al x Ga1–x N, 0 ≤ x ≤ 1) can emit light covering the ultraviolet spectrum from 210 to 360 nm. However, these emitters have not fulfilled their full promise to replace the toxic and fragile mercury UV lamps due to their low efficiencies. This study demonstrates a promising approach to enhancing the luminescence efficiency of AlGaN multiple quantum wells (MQWs) via the introduction of a lateral-polarity structure (LPS) comprising both III and N-polar domains. The enhanced luminescence in LPS is attributed to the surface roughening, and compositional inhomogeneities in the N-polar domain. The space-resolved internal quantum efficiency (IQE) mapping shows a higher relative IQE in N-polar domains and near inversion domain boundaries, providing strong evidence of enhanced radiative recombination efficiency in the LPS. These experimental observations are in good agreement with the theoretical calculations, where both lateral and vertical band diagrams are investigated. This work suggests that the introduction of the LPS in AlGaN-based MQWs can provide unprecedented tunability in achieving higher luminescence performance in the development of solid state light sources.

Lateral-Polarity Structure of AlGaN Quantum Wells: A Promising Approach to Enhancing the Ultraviolet Luminescence / W. Guo, H. Sun, B. Torre, J. Li, M. Sheikhi, J. Jiang, H. Li, S. Guo, K.-. Li, R. Lin, A. Giugni, E. Di Fabrizio, X. Li, J. Ye. - In: ADVANCED FUNCTIONAL MATERIALS. - ISSN 1616-301X. - 28:32(2018 Jun 08). [10.1002/adfm.201802395]

Lateral-Polarity Structure of AlGaN Quantum Wells: A Promising Approach to Enhancing the Ultraviolet Luminescence

A. Giugni;
2018

Abstract

Aluminum-gallium-nitride alloys (Al x Ga1–x N, 0 ≤ x ≤ 1) can emit light covering the ultraviolet spectrum from 210 to 360 nm. However, these emitters have not fulfilled their full promise to replace the toxic and fragile mercury UV lamps due to their low efficiencies. This study demonstrates a promising approach to enhancing the luminescence efficiency of AlGaN multiple quantum wells (MQWs) via the introduction of a lateral-polarity structure (LPS) comprising both III and N-polar domains. The enhanced luminescence in LPS is attributed to the surface roughening, and compositional inhomogeneities in the N-polar domain. The space-resolved internal quantum efficiency (IQE) mapping shows a higher relative IQE in N-polar domains and near inversion domain boundaries, providing strong evidence of enhanced radiative recombination efficiency in the LPS. These experimental observations are in good agreement with the theoretical calculations, where both lateral and vertical band diagrams are investigated. This work suggests that the introduction of the LPS in AlGaN-based MQWs can provide unprecedented tunability in achieving higher luminescence performance in the development of solid state light sources.
inversion domain boundaries (IDBs); lateral-polarity structures (LPSs); luminescence intensity; multiple quantum wells; ultraviolet light
Settore FIS/03 - Fisica della Materia
Settore ING-INF/01 - Elettronica
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/825624
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