Milliwatt-Level 230-nm AlGaN-Based Far-Ultraviolet Micro-LEDs

Far-ultraviolet light-emitting diodes hold great promise for applications in ultraviolet lithography, secure optical communication, and sterilization, owing to their minimal adverse effects on human tissues. However, producing milliwatt-level optical output at wavelengths below 240 nm remains a considerable technical challenge. In this study, we present the design, fabrication, and characterization of AlGaN-based far-ultraviolet micro-light-emitting diodes emitting at 230 nm. The finite-difference time-domain simulations indicated that reducing the mesa size improves light extraction efficiency. Based on these findings, the 30-μm mesa arrays were fabricated, achieving a peak optical output power of 2.8 mW at 250 mA and a peak emission wavelength of 230 nm. To the best of our knowledge, this result represents the shortest emission wavelength reported for milliwatt-level far-ultraviolet micro-light-emitting diodes. These results demonstrate a major step forward in realizing compact, efficient, and high-performance far-ultraviolet light sources, with strong potential for next-generation applications in public health, environmental safety, and biomedical technologies.