A Review of Challenges, Solutions, and Improvements in the Performance of Deep Ultraviolet Semiconductor Laser Diodes (DUV LDs)

As eco-friendly light sources, AlGaN-based deep ultraviolet laser diodes (AlGaN DUV LDs) employing aluminum gallium nitride that emit between 200 and 300 nm have seen various applications in replacing the traditional mercury DUV light sources, such as photolithography, fluorescence microscopy, and water purification. In this review, we present structures, applications, and advantages of the AlGaN DUV LDs. In addition, limitations and challenges of the AlGaN DUV LDs will be covered. A comparative analysis of the previous researchers’ work regarding strategies that include various designs of electron blocking layers (EBLs), cladding layers, waveguides, and quantum barriers in enhancing the performance of DUV LDs will be reviewed, and the underlying physics of these designs in improving the performance of AlGaN DUV LDs will be discussed.