Impact of the number of well-barrier pair in the MQWs on the carrier distribution and confinement for the AlGaN-based far-UVC LEDs

Abstract

AlGaN-based far-UVC LEDs are urgently in demand recently. However, as the wavelength decreases below 250 nm, the EQE experiences a significant decrease due to the increasing difficulty of realizing high-efficiency doping and high crystal quality with increasing Al content, resulting in severe carrier non-uniform distribution in the MQWs and limiting the radiative recombination. Here, we investigate the effect of the number of well-barrier pair in the MQWs on the performance of AlGaN-based far-UVC LEDs regarding carrier distribution and confinement. The results indicate that an insufficient number of well-barrier pair in the MQWs will lead to excessive carrier injection and insufficient carrier confinement, and an excessive number of well-barrier pairs will make it difficult for carriers to diffuse to the distal quantum wells. It is found that the MQWs with six pairs of well-barrier may be more suitable for far-UVC LEDs. This study provides a feasible direction to optimize far-UVC LEDs.