High Wall-Plug Efficiency AlGaN Deep Ultraviolet Micro-LEDs Enabled by an Etched Reflective Array Design for High Data Transmission
Y.L. Yang, Yuqi Hou, Feng Wu, Zhihua Zheng, Shizhou Tan, Dan‐Xia Xu, Linlin Xu, Chao Shen, Nan Chi, Jiangnan Dai, Changqing Chen
Abstract
AlGaN deep ultraviolet light-emitting diodes (DUV LEDs) have potential applications in free-space communication, but their current limited efficiency restricts the further development of free-space ultraviolet communication (FSUC) applications. In this work, an etched reflective array (ERA) strategy has been proposed in DUV micro-LEDs with various pixel sizes of 20, 30, and 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> m, to enhance the efficiency via etching the p-GaN layer to reduce light absorption and fabricating full-spatial omnidirectional reflector (FSODR) to increase light extraction. The 20- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> m DUV micro-LEDs with ERA strategy exhibit a light output power (LOP) of 39.9 mW at 160 mA and a record high wall-plug efficiency (WPE) of 8.3% at 5 mA. Critically, both the transverse-magnetic (TM) and transverse-electric (TE) mode light intensity are significantly enhanced by 52.59% and 46.29%, respectively, compared with the device without ERA strategy. Furthermore, simulation results show that the light extraction efficiency (LEE) of TM-and TE-polarized light for the 20- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> m DUV micro-LEDs with ERA strategy are enhanced by 48.66% and 46.05%, respectively. In addition, this device achieves a high data transmission rate of 3.819 Gbps in FSUC.