Effects of polarization field distribution on photoelectric properties of InGaN light-emitting diodes

Abstract

Effects of the polarization field distribution in the quantum well layer of InGaN light-emitting diodes (LEDs) on their photoelectric properties are numerically studied. Specifically, the polarization and built-in electricfield distributions, energy band diagrams, carrier concentrations, radiative recombination rate, carrier current density, electroluminescence (EL) spectra, and internal quantum efficiency (IQE) are investigated. The simulation results suggest that the triangular polarization field distribution contributes to uniform carrier distribution in the quantum wells, which inhibits electron current leakage and enhances radiative recombination. In addition, the effects of the polarization field on InGaN multiple quantum wells (MQWs) are effectively suppressed by implementation of triangular MQWs, which leads to minimization of the resulting efficiency droop. LEDs incorporated with triangular MQWs with gallium face-oriented inclination band profiles exhibit a 128% improvement in EL intensity at 20 mA and a 9% reduction in droop at 100 mA in comparison to the conventional square-MQW LEDs.