Thermal droop in high-quality InGaN LEDs

Thermal droop is investigated in high-quality InGaN light-emitting diodes (LEDs). To determine whether it is caused by intrinsic variations in recombination or by transport effects, photoluminescence and electroluminescence measurements are compared. The former does not show signs of pronounced thermal droop, with a near-constant internal quantum efficiency and recombination lifetime, regardless of temperature. In contrast, strong thermal droop is observed in the latter, pointing to transport effects as a leading contributor. Finally, high-efficiency LEDs with near-ideal thermal droop are demonstrated.