Numerical study on photoelectric properties of semi-polar 101̄1 green InGaN light-emitting diodes with quaternary AlInGaN quantum barriers

Abstract

Semi-polar 101̄1 green InGaN light-emitting diodes with different quantum barrier materials were numerically investigated by considering the In composition fluctuation model. For the green light-emitting diode using quaternary Al0.05In0.1Ga0.85N quantum barriers with low Al content, the electric field was reduced, the carrier distribution was appropriately modified, and the efficiency droop was significantly alleviated. In particular, the band pulldown was relieved, and the Fermi levels were flatter, which elevated the electron confinement and decreased the hole injection potential barrier, further promoting hole transport. Moreover, the carrier distribution was more homogeneous and no longer concentrated in the last quantum well, resulting in a reduced nonradiative recombination rate and minimal turn-on voltage. Finally, the internal quantum efficiency was further enhanced by increasing the radiative recombination and thus the efficiency decreased by only 9.1% at a current density of 1000 A/cm2. The proposed structure using quaternary Al0.05In0.1Ga0.85N with low Al molar fraction as a quantum barrier showed great potential for overcoming the “green gap” problem and application in high-power scenarios.