III-Nitride light-emitting devices on patterned sapphire substrates

Characterization of the GaN-based light-emitting diodes (LEDs) grown on patterned sapphire substrates (PSSs) using metalorganic chemical vapor deposition have been explored in this chapter. Dry and wet etching methods were developed to fabricate the PSSs. Conventional and flip-chip device configurations of the PSS-nitride LEDs were discussed. Further improvements in defect density and internal quantum efficiency of ultraviolet emitters can be achieved via a combination of epitaxial lateral overgrowth (ELOG) and PSS techniques. These results exhibit that the improved light extraction efficiency by PSS and the reduced dislocation density by ELOG have become the key technology in the high-efficiency solid-state lighting field.