High-efficiency vertical GaN slab light-emitting diodes using self-coherent directional emitters

We demonstrate a highly-efficient, large-area (1x1 mm(2)) GaN slab light-emitting diode using a vertically directional emitter produced from constructive interference. The vertical radiation can be coupled effectively into leaky modes from the beginning and thus a high-extraction efficiency can be expected with reduced material absorption. The far-field measurements show that the desired vertical emission profiles are obtained by varying the thickness of the dielectric layer between the emitter and bottom silver mirror. With the combination of a light extractor of a randomly textured surface, the output power was increased similar to 1.4 fold compared to a non-patterned device at a standard current of 350 mA without electrical degradation. (C) 2010 Optical Society of America