Light extraction enhancement of GaN-based flip-chip light-emitting diodes using diffused nanorod reflector

Diffused ZnO nanorod reflectors were designed and used in conventional flip-chip light-emitting diodes (FCLEDs) and FCLEDs with a flat reflector. The light output power and the light distribution of the resulting FCLEDs were improved by using the diffused ZnO nanorod reflectors owing to the light scattering of the roughened highly reflective Al metal and the low refractive ZnO nanorod array. Compared with the conventional FCLEDs and the FCLEDs with a flat reflector, the light output power was enhanced by 56.6 and 11.7% for the FCLEDs with a diffused 500-nm-long ZnO nanorod reflector, respectively.