Abstract

LEDs fabricated from gallium nitride have lead to the realization of high-efficiency white solid-state lighting. Currently, GaN white LEDs exhibit luminous efficacy greater than 150 lm/Watt, and external quantum effiencies higher than 60%. This has enabled LEDs to compete with traditional lighting technologies such as incandescent and CFL. Further improvements in materials quality and cost reduction are necessary for wide-spread adoption of LEDs for lighting. A review of the unique polarization anisotropy in GaN is included for the different crystal orientations. Emphasis on nonpolar LEDs will highlight high-power violet and blue emitters and considers the effects of indium incorporation and substrate miscut. Semipolar GaN materials have enable the development of LEDs in green, and recent achievements of green laser diodes at 520nm.

© 2013 Optical Society of America