Full wafer scale electroluminescence properties of AlGaN-based deep ultraviolet LEDs with different well widths.

Abstract

Deep ultraviolet (DUV) LEDs have great potential in sterilization, water, air purification, and other fields. In this work, DUV LED wafers with different quantum well (QW) widths were grown by metal-organic chemical vapor deposition. It is found that the light output power (LOP) and peak wavelength of all chips are not only related to the QW thickness but also affected by warpage. For the first time, to the best of our knowledge, a positive correlation between the LOP and peak wavelength of DUV LED chips on the same wafer was observed, which is very important for improving the yield of DUV LEDs and reducing costs. Furthermore, the influence of QW thickness on the external quantum efficiency (EQE) of DUV LED has also been investigated. As the thickness of the QW increases, the exciton localization effect decreases and the quantum confinement Stark effect increases. Consequently, DUV LED wafers with a QW thickness of 2 nm have the highest EQE and yield. These findings not only help to improve the efficiency of DUV LEDs but also provide new insights for evaluating the performance of DUV LED wafers.