J. Rass, M. Guttmann, H.K. Cho, J. Ruschel, T. Kolbe, K. Gehrke, T.A. Musengezi, and S. Einfeldt

Published in:

Appl. Phys. Lett., vol. 127, no. 16, pp. 161102, doi:10.1063/5.0285251 (2025).

Abstract:

The emission behavior of arrays of far-UVC micro-LEDs emitting at 234 nm has been studied and compared to large area LEDs. The use of the micro-LEDs enhanced the light extraction efficiency by a factor of 2.5 for mesa diameters of 1.5 µm due to a redirection and extraction of TM polarized photons. This redirection also reduces the viewing angle of the emission from the chip from 140° down to 90°. The coupling of the far-UVC light into multimode fibers of 400–910 µm diameter was found to be two times more efficient due to the more directional emission when micro-LED arrays are used, and an overall enhancement of light emission from the fiber by a factor of five was demonstrated for a 1.5 µm micro-LED array in combination with a 910 µm fiber, resulting in a peak power of 0.3 mW from the fiber when the LED was operated at 50 mA and above 1 mW at 200 mA.

© 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/). https://doi.org/10.1063/5.0285251
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