Temperature-dependent decrease in efficiency in power blue InGaN/GaN LEDs

Temperature-dependent decline in the external quantum efficiency (EQE) of blue light-emitting diodes, which is at a maximum at $j<$ 10 A/cm$^2$ and becomes stronger with temperature increasing to 400 K, is due to the buildup of the loss for the nonradiative recombination upon carrier tunneling that involves traps and phonons. As the $p$–$n$ junction becomes open at $j>$ 40 A/cm$^2$ the decline in the external quantum efficiency in the continuous-wave and pulsed modes is determined by the loss in nonequilibrium filling by delocalized carriers of states associated with the lateral inhomogeneities in the composition of the solid solution outside the space-charge region, as well as by the loss due to the interaction of delocalized carriers with extended defects.