Continuous Wave Milliwatt Power AlGaN Light Emitting Diodes at 280 nm

We report on deep ultraviolet light emitting diodes using AlGaN multiple quantum well active regions and with peak emission at 280 nm. A new buffer layer and active region design resulted in flip-chip devices with continuous wave powers as high as 0.85 mW for a pump current of 20 mA and a record external quantum efficiency over 1%. The power saturated at 5 mW for a dc pump current of 200 mA.