Improve GaN-based Green Micro-LEDs Performance with AlGaN/InGaN Multiple Quantum Wells Structure by V-pits Engineering

The V-pits have been widely reported as a special structure in GaN wurtzite materials, which can improve hole injection efficiency and screen non-radiative recombination centers. Therefore, it is of great importance to utilize the characteristics of V-pits and study its growth mechanism for improving the opto-electronic performance and luminous efficiency of GaN-based micro light-emitting diodes (μ-LEDs). In this work, we have fabricated green AlGaN quantum barrier (QB) μ-LEDs to introduce V-pits engineering and investigated the opto-electrical performance and intrinsic mechanisms. The results of low-temperature EL and SEM measurements indicated that the introduction of Aluminum in QBs leads to better hole injection efficiency due to increasing the V-pits area ratio and more uniform carrier distribution within QWs. The CL and EDX results show that AlGaN QB can form higher potential barrier height between side-wall MQWs and c-plane MQWs, thereby enhancing the V-pits screening effect. The EL characteristics indicate that there is a better EQE, lower forward voltage and better efficiency-droop ratio in AlGaN QB μ-LEDs. Thermal resistance, junction temperature and aging tests indicate that AlGaN QB μ-LEDs have better thermal stability and lifespan. These results provide a reference for improving the quantum efficiency and opto-electronic performance of GaN-based green μ-LEDs by V-pits engineering.