Milliwatt power AlGaN quantum well deep ultraviolet light emitting diodes

We report on the development of deep ultraviolet AlGaN multiple quantum well light emitting diodes on sapphire with peak emission wavelength from 278 nm to 340 nm. The high quality of the n(+)-AlGaN buffer layer was achieved using a new pulsed atomic layer epitaxy growth technique to deposit a high quality AlN buffer layers followed by a strain relief AlN/AlGaN superlattice. These devices exhibited pulsed powers as high as 3 mW, 10 mW and 13 mW for 1 A of pumping current. Under pulsed pumping, the external quantum efficiencies of about 0.1% (278 nm), 0.45% (325 nm) and 0.55% (340 nm) represent record high values and the shortest LED emission wavelengths to date. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.