Directional and controllable edge-emitting ZnO ultraviolet random laser diodes

Room-temperature ultraviolet random lasing action is demonstrated from a p-GaN/annealed i-ZnO: Al (3%)/n-ZnO: Al (5%) buried heterojunction diode with a 2 mu m rib waveguide. Excellent electrical-to-optical conversion efficiency is achieved by strong electrical and optical confinement of a buried heterojunction rib waveguide structure. Hence, emission intensity (threshold current) can be enhanced (reduced) by similar to 9 times (similar to 40%). Directional emission as well as controllability on the number of the random lasing modes can also be achieved. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3356221]