Efficient coupling of disorder states to excitons in an InGaN nanostructure

InxGa1-xN disks in GaN nanowires (DINWs) have emerged as a viable technology for on-chip tunable visible spectrum emission without the use of a phosphor. Here, we present a study of the optical emission and absorption dynamics in DINWs that incorporates the important role of background disorder states. The optical emission in the system is dominated by quantum-confined excitons, however, we show here that the excitons are coupled to a large density of background disorder states. Rapid nonradiative decay (compared to other decay rates such as spontaneous emission) from disorder states into excitons is observed after optical excitation of our sample that dominates the nonlinear absorption dynamics. Because disorder states are ubiquitous in InGaN layers, we believe that this result reveals an important decay channel that should be incorporated in future modeling and engineering of InGaN-based optical devices in general.