Enhanced output power of near-ultraviolet LEDs with AlGaN/GaN distributed Bragg reflectors on 6H-SiC by metal-organic chemical vapor deposition

摘要

Near-ultraviolet (UV) InGaN/AlGaN multiple quantum well (MQW) LEDs with 30 pairs AlGaN/GaN distributed Bragg reflectors (DBRs) were grown on 6H-SiC substrate by metal-organic chemical vapor deposition. A thin SiN_x interlayer was introduced between the DBRs and n-GaN layer of the LED to reduce the threading dislocation density and result in enhancement the internal quantum efficiency (η_(int)) of the InGaN/AlGaN LED. The result indicates that the light output power for the LED with DBRs and SiN_x interlayer was approximately 56% higher (at 350 mA) than the LED without DBRs and SiN_x interlayer on 6H-SiC substrate, and this significant improvement in performance is attributed not only to the light extraction enhancement via the DBRs but also due to improve epilayer crystalline quality.