The Influence of InGaN Interlayer on the Performance of InGaN/GaN Quantum-Well-Based LEDs at High Injections

Introducing a thin InGaN interlayer with a relatively lower indium content between the quantum well (QW) and barrier results in a step-like InxGa1-xN/GaN potential barrier on one side of the QW. This change in the active region leads to a significant shift in photoluminescence (PL) and electroluminescence (EL) emissions to a longer wavelength compared with the conventional QW based light-emitting diodes. More importantly, an improvement against efficiency droop and an enhancement in light output power at the high-current injection are observed in the modified light-emitting diode structures. The role of the inserted layer in these improvements is investigated by simulation in detail, which shows that the creation of more sublevels in the valence band and the increase of hole concentration inside QWs are the main reasons for these improvements.