Milliwatt power 233 nm AlGaN-based deep UV-LEDs on sapphire substrates
Appl. Phys. Lett., vol. 117, no. 11, pp. 111102, DOI: 10.1063/5.0015263 (2020).
Copyright © 2020 Author(s). Published under license by AIP Publishing.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Deep UV-LEDs (DUV-LEDs) emitting at 233 nm with an emission power of (1.9±0.3) mW and an external quantum efficiency of (0.36±0.07) % at 100 mA are presented. The entire DUV-LED process chain was optimized including the reduction of the dislocation density using epitaxially laterally overgrown AlN/sapphire substrates, development of vanadium-based low resistance n-metal contacts, and employment of high thermally conductive AlN packages. Estimated device lifetimes above 1500 h are achieved after a burn-in of 100 h. With the integration of a UV-transparent lens, a strong narrowing of the far-field pattern was achieved with a radiant intensity of 3 mW/sr measured at 20 mA.
1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
2 UVphotonics NT GmbH, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany
3 Institute of Solid State Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
Quantum efficiency, Light emitting diodes, I-V characteristics, Flip chip, Semiconductor device fabrication