Enhanced luminescence of GaN-based light-emitting diode with a localized surface plasmon resonance

We report on the development of GaN-based light-emitting diode with a Au nanoparticles arrayed layer for increasing the light output. Au nanoparticles are used for enhancing the light extraction efficiency. Au nanoparticles induce a localized surface plasmon resonance (LSPR). This effect performs extracting the trapped light in a device, and then, enhances the luminous efficiency of LEDs. Au nanoparticles arrayed layers were fabricated by sputtering and annealing processes. The size and filling factor of particles can be controlled by the three conditions, such as a deposited film thickness, annealing temperature and time. These are important factors to determine the efficiency, because a LSPR depends on both of the size and density of particles. With a 20 mA current injected onto the LED, an enhancement of 1.8 times in electroluminescence intensity was observed. By comparing this with a conventional LED, both LSPR effect and scattering by rough surface contribute to the enhancement of emission.