Performance enhancement of InGaN-based light-emitting diodes with InGaN/AlInN/InGaN composition-graded barriers

A new structure with InGaN/AlInN/InGaN composition-graded barriers for a nitride-based light-emitting diode (LED) has been proposed and analyzed numerically. The energy band diagrams, the electrostatic fields, the carrier concentrations in the quantum well, the light output power and the internal quantum efficiency are investigated. Numerical simulation results suggest that the new structure contributes to a more uniform carrier concentration distribution, a smaller polarization electrostatic field and a more effective confinement of electrons in the active region. As a result, LEDs with this new structure attain a higher optical output power and a reduced efficiency droop of 24.7% compared with 66.6% in a conventional LED.