Significantly boosted external quantum efficiency of AlGaN-based DUV-LED utilizing thermal annealed Ni/Al reflective electrodes

摘要

Improvement of light extraction efficiency of deep ultraviolet light-emitting-diodes (DUV-LEDs) was obtained by adopting a Ni/Al reflective electrode. Optical reflectivity up to 78.1% at 277 nm was achieved. The enhanced reflectivity after thermal annealing was ascribed to the formation of Ni clusters embedded inside the Al matrix as revealed by the correlation between the surface morphology and chemical stoichiometry. The peak external quantum efficiency of a 277 nm DUV-LED incorporating annealed Ni/Al reflective electrodes reaches 3.03%, which is 44% higher than that with conventional Ni/Au p-electrodes, revealing itself as a promising candidate in the realization of high-efficiency DUV emitters.