Abstract

The realization of semiconductor laser diodes and light-emitting diodes that emit short-wavelength ultraviolet light is of considerable interest for a number of applications including chemical|[sol]|biochemical analysis, high-density data storage and material processing. Group III nitride materials are one of the most promising candidates for fabricating such devices. Here we describe an AlGaN multiple-quantum-well laser diode that emits light at 342|[nbsp]|nm, the shortest wavelength ever reported for an electrically driven laser diode. To fabricate the laser, a low-dislocation-density AlGaN layer with an AlN mole fraction of 0.3 was grown on a sapphire substrate using a hetero facet-controlled epitaxial lateral overgrowth (hetero-FACELO) method. An AlGaN multiple-quantum-well structure was then grown on the high-quality AlGaN layer. Lasing at a wavelength of 342.3|[nbsp]|nm was observed under pulsed current mode at room temperature.