Investigation of Efficiency Droop Behaviors of InGaN/GaN Multiple-Quantum-Well LEDs With Various Well Thicknesses

Efficiency droop behavior of InGaN/GaN multiple-quantum-well LEDs with various well thicknesses is discussed. It is demonstrated that LED samples with thinner well structures possess higher external quantum efficiencies with stronger droop behaviors. The efficiency droop behavior is contributed by dislocation recombination, Auger recombination in an active region, and carrier overflow out of an active region. Simulation results suggest that at the current density region of 10-100 A/cm², Auger recombination is a dominant mechanism for efficiency droop behavior, while at high current density region of 100-200 A/cm², carrier overflow starts to be the major mechanism for the change of efficiency droop behaviors.