Quantitative Analysis of Initial Short-Term Aging Behavior and Its Implication for the Efficiency Droop in Blue Light-Emitting Diodes

We have quantitatively analyzed the short-term aging behavior of blue light-emitting diodes using the current-component analysis method. The internal quantum efficiency and luminescence output decrease monotonically with the aging time and are stabilized at low operation current, owing to the increase and subsequent stabilization in the tunneling and nonradiative currents, while they show complicated behavior at high operation current due to the interplay of different changing rates in the radiative and nonradiative recombination current components. The current-component analysis enables both the quantitative understanding of the aging behavior and the identification of the aging mechanisms. Also shown is that the loss current, which is responsible for the efficiency droop, is approximately proportional to the cube of the injected carrier concentration. This suggests that the origin of the efficiency droop is a three-carrier process.