The 2020 UV emitter roadmap
J. Phys. D: Appl. Phys., vol. 53, no. 50, pp. 503001 (2020).
Copyright © 2020 IOP Publishing Ltd Printed in the UK.
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Solid state UV emitters have many advantages over conventional UV sources. The (Al,In,Ga)N material system is best suited to produce LEDs and laser diodes from 400 nm down to 210 nm - due to its large and tuneable direct band gap, n- and p-doping capability up to the largest bandgap material AlN and a growth and fabrication technology compatible with the current visible InGaN-based LED production. However AlGaN based UV-emitters still suffer from numerous challenges compared to their visible counterparts that become most obvious by consideration of their light output power, operation voltage and long term stability. Most of these challenges are related to the large bandgap of the materials. However, the development since the first realization of UV electroluminescence in the 1970s shows that an improvement in understanding and technology allows the performance of UV emitters to be pushed far beyond the current state. One example is the very recent realization of edge emitting laser diodes emitting in the UVC at 271.8 nm and in the UVB spectral range at 298 nm. This roadmap summarizes the current state of the art for the most important aspects of UV emitters, their challenges and provides an outlook for future developments.
1 IMaSS, Nagoya University, Nagoya, 464-8603, Japan
2 Nagoya University, Nagoya, 464-8601, Japan
3 Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, United States of America
4 Department of Information Engineering, University of Padova, via Gradenigo 6/b, 35131, Padova, Italy
5 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489, Berlin, Germany
6 Department of Electronic Science and Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto, 615-8510, Japan
7 UV Craftory Co., Ltd., Nagoya 464-0015, Japan
8 RIKEN, 2-1 Hirosawa Wako, Saitama 351-0198, Japan 9 Marubun Corporation, 8-1 Oodenma-cho, Nihonbashi, Chuo Ward, Tokyo 109-8577, Japan
10 Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstr. 36, 10623, Berlin, Germany
11 Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
12 Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Drive, Atlanta, GA 30332, United States of America
13 Georgia Institute of Technology, School of Electrical and Computer Engineering, Georgia Tech-CNRS, UMI 2958 57070, Metz, France
14 Tyndall National Institute and School of Engineering, University College Cork, Cork, Ireland
15 Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210,United States of America
16 Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210,United States of America
17 Adroit Materials, Inc., 2054 Kildaire Farm Rd, Suite 205, Cary, NC 27518, United States of America
18 Department of Electrical Engineering/Computer Science and CINSaT, University of Kassel, Wilhelmshoeher Allee 71, D-34121, Kassel, Germany
19 Department of Electronics and Communication Engineering, Indian Institute of Technology, Roorkee, Uttarakhand, 247667 India
20 Institute of Functional Nanosystems, Ulm University, 89069, Ulm, Germany
21 Crystal IS Inc., 70 Cohoes Ave., Green Island, NY 12183, United States of America
22 Asahi Kasei Corporation, Fuji 416-8501, Japan
23 Department of Electrical and Electronic Engineering, University of Bath, Bath BA2 7AY, United Kingdom
24 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
25 National Taiwan University, Institute of Photonics and Optoelectronics and Department of Electrical Engineering
26 Electronics Materials and Devices Laboratory, PARC, a Xerox Company, 3333 Coyote Hill Road, Palo Alto, CA 94304, United States of America
ultraviolet, light emitting diodes, InGaN, UV-LED, AlGaN.