Investigation of blue InGaN light-emitting diodes with AlGaN barriers of the increasing Al composition

The characteristics of blue InGaN light-emitting diodes with AlGaN barriers of different step-like growth range Al composition and gradually increasing Al composition are investigated numerically. The simulation results indicate that the enhanced electron confinement and hole injection efficiency are mainly attributed to the mitigated downward band bending of the last barrier induced by polarization field, and the improved carrier distribution is owing to the increasing blocking for electrons as well as the decreasing blocking for holes. What's more, the output power, the distribution and rate of radiative recombination and the efficiency droop are markedly improved.