A Review of AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes on Sapphire

By Yosuke Nagasawa, Akira Hirano. Applied Sciences, 2018

174 citations recorded by the source corpus.

This paper reviews the progress of AlGaN-based deep-ultraviolet (DUV) light emitting diodes (LEDs), mainly focusing in the work of the authors’ group. The background to the development of the current device structure on sapphire is described and the reason for using a (0001) sapphire with a miscut angle of 1.0° relative to the m-axis is clarified. Our LEDs incorporate uneven quantum wells (QWs) grown on an AlN template with dense macrosteps. Due to the low threading dislocation density of AlGaN and AlN templates of about 5 × 108/cm2, the number of nonradiative recombination centers is decreased. In addition, the uneven QW show high external quantum efficiency (EQE) and wall-plug efficiency, which are considered to be boosted by the increased internal quantum efficiency (IQE) by enhancing carrier localization adjacent to macrosteps. The achieved LED performance is considered to be sufficient for practical applications. The advantage of the uneven QW is discussed in terms of the EQE and IQE. A DUV-LED die with an output of over 100 mW at 280–300 nm is considered feasible by applying techniques including the encapsulation. In addition, the fundamental achievements of various groups are reviewed for the future improvements of AlGaN-based DUV-LEDs. Finally, the applications of DUV-LEDs are described from an industrial viewpoint. The demonstrations of W/cm2-class irradiation modules are shown for UV curing.

Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/ea9e0add15d4a5659d02c1f0c4392c44a9d93f03

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In Condensed Matter Physics

1. M. Kneissl
2. Akira Hirano
3. Matteo Meneghini
4. Hideki Hirayama
5. Ferdinand Scholz
6. J. Rass

In Electronic, Optical and Magnetic Materials

1. M. Kneissl
2. Akira Hirano
3. Matteo Meneghini
4. Ferdinand Scholz

In Materials Chemistry

1. M. Kneissl
2. Ferdinand Scholz

Citations in the corpus

• The 2020 UV emitter roadmap (2020, background): “Also, the results of reliability tests have been reported for 265 nm UVC LEDs with a p-GaN contact layer on sapphire [113, 122].”