In this letter, the authors report the fabrication of GaN-based light-emitting diodes (LEDs) with mesh indium-tin-oxide p-contact and nanopillars on patterned sapphire substrate. Using hydrothermal ZnO nanorods as the etching hard mask, the authors successfully formed vertical GaN nanopillars inside the mesh regions and on the mesa-etched regions. It was found that 20-mA forward voltage and reverse leakage currents observed from the proposed LED were only slightly larger than those observed from the conventional LEDs. It was also found that output power of the proposed LED was more than 80% larger than that observed from conventional LED prepared on flat sapphire substrate.
