GaN based UV-LEDs with Ni/Au Nanomeshes as Transparent p-type Electrodes

Ni/Au nanomesh (NM) is utilized as the p-type contact in the ultraviolet (UV)-LEDs for improving the light extraction efficiency. The substitution of conventional planar Ni/Au p-type electrode with highly ordered, large scalable Ni/Au NMs results in enhanced light transmission in the p-type contact region of the UV-LEDs. Transmission over 75% is demonstrated for Ni/Au-NM thin film coated sapphire substrate, whereas light is totally blocked by conventional planar Ni/Au thin film. Linearized I-V characteristic between p-GaN and Ni/Au NMs is achieved by appropriate thermal annealing of the contact, and specific contact resistivity of 0.90 omega cm(2) is reported. UV-LED incorporated with Ni/Au NMs exhibits higher output power than that with planar contact due to enhanced light transmission through the metal network structure. Finally, simulation results suggest good agreement with experimental data, illustrating that Ni/Au NMs can serve as a potential candidate in the development of high efficiency UV optoelectronic devices.