Efficient InGaN-based yellow-light-emitting diodes

Realization of efficient yellow-light-emitting diodes (LEDs) has always been a challenge in solid-state lighting. Great effort has been made, but only slight advancements have occurred in the past few decades. After comprehensive work on InGaN-based yellow LEDs on Si substrate, we successfully made a breakthrough and pushed the wall-plug efficiency of 565-nm-yellow LEDs to 24.3% at 20  A/cm2 and 33.7% at 3  A/cm2. The success of yellow LEDs can be credited to the improved material quality and reduced compressive strain of InGaN quantum wells by a prestrained layer and substrate, as well as enhanced hole injection by a 3D pn junction with V-pits.