Band-Edge Luminesce in Quaternary AlInGaN Light-Emitting Diodes

Operation of InGaNmultiple-quantum-well(MQW)light-emitting diodes(LEDs) with quaternary AlInGaN barriers at room and elevated temperatures is reported. The devices outperform conventional GaN/InGaN MQWLEDs, especially at high pump currents. From the measurements of quantum efficiency and total emitted power under dc and pulsed pumping, we show the emission mechanism for quaternary barrier MQWs to be predominantly linked to band-to-band transitions. This is in contrast to localized state emission observed for conventional InGaN/InGaN and GaN/InGaN LEDs. The band-to-band recombination with an increased quantum-well depth improves the high-current performance of the quaternary barrier MQWLEDs, making them attractive for high-power solid-state lighting applications