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ELOS 2023

Wei Liu

Wei Liu, Speaker at Optics Conference
Northwestern Polytechnical University, China
Title : Investigation on GaN/AlGaN ultraviolet light-emitting diodes with different thickness of first AlGaN barrier layer


The influence of thickness of the first AlGaN barrier layer, which is closest to the n-type GaN layer, on the luminescence characteristics of ultraviolet GaN/AlGaN multiple-quantum-well (MQW) light-emitting diodes (LEDs) is investigated numerically. Generally, for the study on the transport of carriers in GaN-based multiple-quantum-well ultraviolet (UV) light-emitting diodes (LEDs), most researches focus on the structure of electron blocking layer (EBL) near p-GaN region, since the leakage of electrons is commonly considered as the main problem in UV LEDs. However, it’s found that the luminescence efficiency of LED is enhanced as the thickness of first AlGaN barrier increases. According to the energy band structures and carrier distributions in the MQW active region, it is found that the hole leakage can be suppressed by the thicker first barrier, which may be ascribed to the increased width and height of the triangular potential barrier induced by the polarization electric field in the first AlGaN barrier layer in Figure 1. Therefore, the concentration of holes in the whole MQW active region is increased, which improves the luminescence efficiency of the ultraviolet LEDs with thick AlGaN first barrier layer.

Audience Take Away Notes :

  • The audience will know better about the working mechanisms of GaN-based ultraviolet light-emitting diodes;
  • My presentation provides a simple and practical solution to improve the performance of ultraviolet light-emitting diodes;
  • Other faculty can use our conclusion to expand their research or teaching.


Dr. Wei Liu is currently an Associate Professor with the School of Microelectronics, Northwestern Polytechnical University, Xi’an, China. His current research interest is the study on the group III-V compound semiconductors for optoelectronic materials and devices, such as avalanche photodiodes and light-emitting diodes.