Nanorod-structured flip-chip GaN-based white light-emitting diodes

To obtain high light output power and high phosphor conversion efficiency of the white light-emitting diodes (WLEDs), various methods including the reflectors and the surface roughness technique were intensively investigated. The improvement results of the relating researches about the reflectors and the surface roughness technique employed in the LEDs were discussed in this article. The light output power of the resulting LEDs with ZnO nanorod diffused reflectors improved 56.6% compared with the conventional LEDs. The LEDs with ZnO nanorod antireflection layer obviously enhanced the light extraction performance. Furthermore, the flip-chip white LEDs (FCWLEDs) with the diffused ZnO nanorod reflector and ZnO nanorod antireflection layer were also proposed in this article. The output power and phosphor conversion efficiency of FCWLEDs with diffused ZnO nanorod reflectors and ZnO nanorod arrays antireflection layer were improved to 23.91 mW and 80.1% compared with FCWLEDs with flat reflectors. These results verified that the both of the diffused ZnO nanorod reflector and the ZnO nanorod array antireflection layer could effectively guide more blue light to improve the light output power and the phosphor conversion efficiency of resulting LEDs.