Cathodoluminescence study for ultraviolet GaN-based MQW LEDs

In this work, a cathodoluminescence (CL) investigation on ultraviolet-emission GaN-based multiple quantum wells (MQWs) Light-Emitting Diodes (LEDs) grown on patterned sapphire substrate is conducted. It was found that the removal of the p-GaN layer promote the electron pumping efficiency, thus resulting in an enhanced energy efficiency. Both numerically and experimentally, it is revealed that the number of the quantum well affects the power efficiency of the LED devices. Furthermore, the experimental results show that 8 QWs contribute the highest peak power efficiency for our designs, and the optimal number may falls into 8 to 12 for different epitaxial structures. The findings in this work proves the potential of the CL-based ultraviolet MQW LEDs with optimized structures and can provides guidelines for designing the high-efficiency deep-UV LED devices.