AlN/GaN/InGaN interface engineering for high-efficiency InGaN-based red quantum wells grown on Si

Abstract

InGaN-based red light-emitting diodes (LEDs) grown on Si have gained tremendous interest for full-color micro-display applications. To achieve efficient red pixels, a major challenge in realizing high-quality InGaN-based red multiple quantum wells (MQWs) is the huge lattice mismatch between high In-content InGaN and GaN, which calls for proper interfacial strain engineering. This work fundamentally reveals that the atomic inter-diffusion driven by tensile stress field at the InGaN QW interface critically degrades the luminescence wavelength and efficiency. To address this, a GaN/AlN hybrid interlayer is developed to facilitate the growth of high-quality InGaN-based red MQWs on Si, which compensates compressive strain and effectively suppresses the atomic redistribution between the AlN interlayer and InGaN QW, thus reducing the interfacial defects and yielding sharply defined MQW interfaces. The vertical red LED chips, featuring InGaN-based MQWs with a hybrid GaN/AlN interlayer presenting a remarkable internal quantum efficiency of 44%, achieved a peak external quantum efficiency up to 8.3% at 621 nm. This work provides a feasible strategy for the epitaxial growth of high performance InGaN-based red LEDs.