Pseudomorphic Al x Ga 1-x N MQW based deep ultraviolet light emitting diodes over sapphire: Pseudomorphic Al x Ga 1-x N MQW based deep ultraviolet light emitting diodes over sapphire

We report on the fabrication of AlGaN-based pseudomorphic light-emitting diodes over sapphire substrate with peak emission at 275 nm. A 0.6 mu m thick n-AlGaN contact layer was grown using a novel pulsed silicon modulation doping technique, which enabled us to achieve a sheet resistance of similar to 500 Omega/square In order to miti-gate current crowding and Joule heating issues, we implemented the pixel-LED design with a total p-active area of 360 mu m x 360 mu m. Packaged devices exhibited light output powers of similar to 7 mW at 100 mA dc pump current. The forward voltage was similar to 8.8 V. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim