III-Nitride p-down green (520 nm) light emitting diodes with near-ideal voltage drop

Abstract

We demonstrate p-down green emitting LEDs with low turn-on voltage enabled by efficient tunnel junctions. Due to the polarization field alignment in the (In,Ga)N/GaN interface with the p-down orientation, the electrostatic depletion barrier for electron and hole injection is reduced when compared with the conventional p-up LEDs. A single (In,Ga)N/GaN heterostructure quantum well active region with a GaN homojunction tunnel junction exhibited very low forward operating voltage of 2.42 V at 20 A/cm2 with a peak electroluminescence emission wavelength of 520 nm for current densities above 100 A/cm2. The bottom tunnel junction with minimal voltage drop enabled excellent hole injection into the bottom p-GaN layer.