Milliwatt power AlGaN-based deep ultraviolet light emitting diodes by plasma-assisted molecular beam epitaxy

We report the development of AlGaN‐based deep ultraviolet LEDs by plasma‐assisted molecular beam epitaxy. The devices were evaluated under bare‐die configuration, placed outside an integrated sphere, and were found to have optical power of 1.3 mW and 1.2 mW at 300 nm and 277 nm, under pulsed driving current of 200 mA and 500 mA, respectively. The external quantum efficiency (EQE) of the 300 nm LED is 0.16% at drive current of 90 mA. These data suggest that AlGaN alloys grown by MBE under excess Ga are capable of producing deep UV‐LEDs with high IQE. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) This Letter reports the growth by plasma‐assisted MBE of UV‐LEDs emitting in the wavelength range between 300 and 277 nm with an output power in excess of 1 mW measured at the wafer level. The active region of such LEDs was grown under Ga‐rich conditions, which lead to band structure potential fluctuations and thus to high internal quantum efficiency.