Low-efficiency-droop InGaN quantum dot light-emitting diodes operating in the “green gap”

Gallium nitride (GaN)-based light-emitting diodes (LEDs) are important for lighting and display applications. In this paper, we demonstrate green-emission (512 nm) InGaN quantum dot (QD) LEDs grown on a c-plane sapphire substrate by metal-organic chemical vapor deposition. A radiative lifetime of 707 ps for the uniform InGaN self-assembled QDs is obtained by time-resolved photoluminescence measurement at 18 K. The screening of the built-in fields in the QDs effectively improves the performance of QD LEDs. These high quantum efficiency and high temperature stability green QD LEDs are able to operate with negligible efficiency droop and with current density up to 106 A∕cm². Our results show that InGaN QDs may be a viable option as the active medium for stable LEDs.