Efficiency droop in InGaN/GaN multiple quantum well light-emitting diodes with nonuniform current spreading

We demonstrate that the efficiency droop phenomenon in multiple quantum well InGaN/GaN
light-emitting diodes (LEDs) may be connected to the current crowding effect. A numerical
model of internal quantum efficiency calculation is presented that takes into account
nonuniform lateral carrier injection in the active region. Based on this model, we examine the
effect of current crowding on the efficiency droop using comparison of simulated internal
quantum efficiency of InGaN LEDs with low and high uniformity of current spreading. The
results of simulations and measurements show that the devices with low uniformity of current
spreading exhibit higher efficiency droop and lower roll-off current value.