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

• Crack-free UV-LED with 30 pairs AlGaN/GaN DBRs grown on 6H–SiC substrate by MOCVD.
• A thin SiNx interlayer was introduced to reduce the threading dislocation density.
• The light output power for UV-LED with DBRs was improve about 56% at 350 mA.
• The DBRs is not only improved efficiency of UV-LEDs, but also can be applied to RCLEDs and VCSELs.

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 SiNx 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 (ηint) of the InGaN/AlGaN LED. The result indicates that the light output power for the LED with DBRs and SiNx interlayer was approximately 56% higher (at 350 mA) than the LED without DBRs and SiNx 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.