Tunnel injection In 0.25 Ga 0.75 N / GaN quantum dot light-emitting diodes

Hole tunnel injection is incorporated in the design of In 0.25 Ga 0.75 N / GaN quantum dot light-emitting diodes with peak emission at λ ∼ 500 nm . Calculations show that cold holes are uniformly injected into all five quantum dot layers in the active region. Measurements were made on devices having different thicknesses, t eff , of the In 0.43 Al 0.57 N hole tunnel barrier. The best performance is exhibited by a device with t eff = 1.5 nm . The maximum external quantum efficiency is 0.66% at 220 A / cm 2 , and an efficiency droop of 20% at 360 A / cm 2 is tentatively attributed to reduced Auger recombination and leakage of hot carriers.