Solution-growth ZnO nanorods for light extraction in GaN-based flip-chip LEDs

A simple and low-cost successive ionic layer adsorption and reaction and hydrothermal method was used to form ZnO nanorods sapphire surface for GaN-based power flip-chip (FC) light-emitting diodes (LEDs).With 350-mA current injection, it was found that the output powers were 361.7 and 448.2 mW for the FC LED without ZnO nanorods and with ZnO nanorods, respectively. The FC LED with ZnO nanorods was 24% larger than that of the FC LED without ZnO nanorods. Furthermore, it was also found that the formation of ZnO nanorods on the surface of sapphire will not degrade the electrical properties.