Improvement of efficiency droop in InGaN/GaN multiple quantum well light-emitting diodes with trapezoidal wells

We investigated InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) with trapezoidal wells to improve the efficiency droop. MQW LEDs with trapezoidal wells showed a lower operating voltage and an improved efficiency droop with a low crossover current density of 5 A cm⁻², which was a significant improvement over conventional LEDs that use rectangular wells. The external quantum efficiency was increased by 20% at a current density of 70 A cm⁻². The improvement in efficiency droop of the MQWs with trapezoidal wells can be attributed to an increased internal quantum efficiency due to the enhanced overlap of the electron and hole wave functions at high current densities.