AlGaN deep-ultraviolet light-emitting diodes

We report on the development of AlGaN based deep ultraviolet (DUV) light-emitting diodes (LEDs) grown by migration-enhanced metalorganic chemical vapor deposition (MEMOCVD). Improved quality of AlGaN has allowed us to achieve milliwatt-power at wavelengths ranging from 365 to 265 nm. For 295 and 280 nm LEDs, record CW powers with wall-plug-efficiency approaching 1.0% were realized. The CW power reached 1.2 and 1.0 mW at 20 mA for 280 and 295 nm LEDs, respectively. A multiple-chip package (UV lamp) emitted CW power of 11 mW at the wavelength of 280 nm. Under pulse operation, the 280 nm UV lamp produced power as high as 56 mW. The CW power levels at 20 mA were 0.5, 0.25 and 0.15 mW for a single-chip 275, 270 and 265 nm LEDs, respectively. A 265 nm UV lamp exhibited a record high CW power exceeding 1.5 mW. The applications of these DUV LEDs in bio-agents detection have been demonstrated and the preliminary results will be presented.