Temperature-dependent nonradiative recombination processes in GaN-based nanowire white-light-emitting diodes on silicon

In this paper, we have performed a detailed investigation of the temperature- and current-dependent emission characteristics of nanowire light-emitting diodes, wherein InGaN/GaN dot-in-a-wire nanoscale heterostructures and a p-doped AlGaN electron blocking layer are incorporated in the devices active region to achieve white-light emission and to prevent electron overflow, respectively. Through these studies, the Auger coefficient is estimated to be in the range of ∼10 ³⁴ cm ⁶ s ¹ or less, which is nearly four orders of magnitude smaller than the commonly reported values of planar InGaN/GaN heterostructures, suggesting Auger recombination plays an essentially negligible role in the performance of GaN-based nanowire light-emitting diodes. It is observed, however, that the performance of such nanowire LEDs suffers severely from Shockley-Read-Hall recombination, which can account for nearly 40% of the total carrier recombination under moderate injection conditions (100Acm ²) at room temperature. The Shockley-Read-Hall nonradiative lifetime is estimated to be in the range of a few nanoseconds at room temperature, which correlates well with the surface recombination velocity of GaN and the wire diameters used in this experiment.