Achieving High Efficiency 253 nm Micro-LED by Multiple Nano AlN Insertion Layers for Applications in Charge Management and Optical Communication

Abstract

Ultraviolet-C micro light-emitting diodes (UVC micro-LEDs) have attracted extensive attention across various fields, including optical communication, aerospace, phototherapy, and sensing. However, the external quantum efficiency (EQE) of UVC micro-LEDs remains suboptimal due to several challenges, such as the limitation of the substrate extraction cone, the lattice mismatch between the substrate and the epitaxial layers, and the sidewall damage. In this work, UVC micro-LEDs with high efficiency, high reliability, and high bandwidth are realized by adding AlN thin layers into the electron blocking layer (EBL), which leads to a record-breaking peak EQE of 3.55% and a peak wall plug efficiency (WPE) of 3.34% at 253 nm. Subsequently, we investigate the degradation mechanism through accelerated aging tests and conduct charge management experiments specifically for the TianQin project. The 6545-h L₇₀ lifetime and the temperature cycle impact experiment further substantiate the high reliability of these UVC micro-LEDs. Additionally, the impressive -3 dB bandwidth of up to 485 MHz and the data rate reaching 1.69 Gbps highlight their potential in UVC communication applications. This research not only offers valuable insights for enhancing the performance of UVC micro-LEDs, but also underscores their significant potential in the field of charge management and UVC communication.