Micro-Trench Deep-Ultraviolet LEDs With Boosted Efficiency for High-Speed Solar-Blind Optical Communication

The deep-ultraviolet (DUV) band presents an untapped opportunity for enhancing optical wireless communication, particularly in outdoor environments where visible light often falls short. To unlock this potential, a highly efficient DUV light source with substantial bandwidth is essential. Herein, we propose an easy-to-fabricate micro-trench DUV light-emitting diode (MT-LED) architecture, having micro trenches on the LED surface incorporating the micro rings with Ni/Au p-pad, which also works as a reflector as well as an interconnect. The embedded micro-trench structure promotes efficient escape of photons from the LED, resulting in improved light output power (LOP), with a significant 1.25 times higher in comparison with conventional LED (C-LED) at a current density of 120 A/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. More importantly, an enlarged bandwidth was also achieved in MT-LED, with a demonstration of 11.7% higher 3 dB optical bandwidth in contrast to the C-LED since the incorporation of micro-trench structure exhibits less resistance-capacitance time constant and a shorter carrier lifetime. Remarkably, the simultaneous improved LOP and enlarged optical bandwidth in MT-LED strongly boost its communication data rate by 54.7%, increasing from 1.240 Gbps (using C-LED) to 1.919 Gbps. The micro-trench structure is essential for developing high-speed, solar-blind optical wireless communication systems, significantly advancing modern connectivity and optical communication networks.