Tunnel injection In0.25Ga0.75N/GaN quantum dot light-emitting diodes

Hole tunnel injection is incorporated in the design of In0.25Ga0.75N/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, teff, of the In0.43Al0.57N hole tunnel barrier. The best performance is exhibited by a device with teff=1.5 nm. The maximum external quantum efficiency is 0.66% at 220 A/cm2, and an efficiency droop of 20% at 360 A/cm2 is tentatively attributed to reduced Auger recombination and leakage of hot carriers.