Enhanced Light Output of Near-Ultraviolet LEDs With Ta2O5/SiO2 Hybrid DBR Reflector

We designed and fabricated AlGaN-based near-ultraviolet light-emitting diodes (LEDs) operating at 368 nm with high output power using Ta ₂ O ₅ /SiO ₂ hybrid distributed Bragg reflectors (DBRs). The output powers of LEDs with eight-pair DBR and hybrid-DBR configurations were increased by 18% and 25% when compared with that of an LED without any DBR. The reflectance of the eight-pair DBR and hybrid-DBR were as high as 99%. In addition, the reflectance of the fabricated hybrid-DBR showed a slight dependence on the incident light wavelength and the angle of incidence. In comparison to the eight-pair DBR, the bandwidth of the hybrid-DBR's reflectance band was broadened by up to 74 nm. Under current injection at 350 mA, output powers of 88, 104, and 110 mW were measured for LEDs without any DBR reflector, with the eight-pair DBR, and with the hybrid-DBR, respectively.