A Review of AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes on Sapphire
Yosuke Nagasawa,Akira Hirano +1 more
TLDR
In this article, the progress of AlGaN-based deep-ultraviolet (DUV) light emitting diodes (LEDs), mainly focusing in the work of the authors' group, is reviewed.Abstract:
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.read more
Citations
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Journal ArticleDOI
The emergence and prospects of deep-ultraviolet light-emitting diode technologies
TL;DR: In this article, the authors reviewed recent progress in the development of AlGaN-based deep-ultraviolet light-emitting devices and described the key obstacles to enhancing their efficiency and how to improve their performance.
Journal ArticleDOI
The 2020 UV emitter roadmap
Hiroshi Amano,Ramon Collazo,Carlo De Santi,Sven Einfeldt,Mitsuru Funato,Johannes Glaab,Sylvia Hagedorn,Akira Hirano,Hideki Hirayama,Ryota Ishii,Yukio Kashima,Yoichi Kawakami,Ronny Kirste,Michael Kneissl,Michael Kneissl,Robert W. Martin,Frank Mehnke,Matteo Meneghini,Abdallah Ougazzaden,Peter J. Parbrook,Siddharth Rajan,Pramod Reddy,Friedhard Römer,Jan Ruschel,Biplab Sarkar,Biplab Sarkar,Ferdinand Scholz,Leo J. Schowalter,Philip A. Shields,Zlatko Sitar,Luca Sulmoni,Tao Wang,Tim Wernicke,Markus Weyers,Bernd Witzigmann,Yuh-Renn Wu,Thomas Wunderer,Yuewei Zhang +37 more
TL;DR: In this article, the state of the art for the most important aspects of UV emitters, their challenges and their outlook for future developments are summarized. But, the development since the first realization of UV electroluminescence in the 1970s shows that an improvement in understanding and technology allows the performance ofUV emitters to be pushed far beyond the current state.
Journal ArticleDOI
Beyond solid-state lighting: Miniaturization, hybrid integration, and applications of GaN nano- and micro-LEDs
TL;DR: In this paper, the authors present a review of the state-of-the-art GaN micro-and nanodevices beyond lighting, including an up-to-date overview on the state of the art.
Journal ArticleDOI
Monolithic Micro Light-Emitting Diode/Metal Oxide Nanowire Gas Sensor with Microwatt-Level Power Consumption.
TL;DR: The smallest fabricated gas sensor showed excellent NO2 sensitivity and robustness to high humidity conditions, which demonstrate its potential for practical applications in mobile internet of things (IoT) devices.
Journal ArticleDOI
AlGaN deep-ultraviolet light-emitting diodes grown on SiC substrates
Burhan K. Saifaddin,Abdullah S. Almogbel,Christian J. Zollner,Feng Wu,Bastien Bonef,Michael Iza,Shuji Nakamura,Steven P. DenBaars,James S. Speck +8 more
TL;DR: The disinfection industry would greatly benefit from efficient, robust, high-power deep-ultraviolet light-emitting diodes (UV-C LEDs) as discussed by the authors, however, the performance of UV-C AlGaN LEDs is limited by poor performance.
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