Enhancing Light Output of GaN-based Light-Emitting Diodes with Nanoparticle-Assembled On-Top Layers.

We present a systemic study on the tailoring of light emission properties of the GaN-based light-emitting diodes (LEDs) with nanoparticle-assembled on-top layers. A layer of silver nanoparticles is deposited on the top of the InGaN/GaN quantum wells (QWs) in gas-phase. The coupling of spontaneous emission from InGaN QWs into the surface plasmon modes of silver nanoparticle layer is demonstrated. The effect of the silver nanoparticle arrays on the extraction efficiency of the emitted light is also investigated. We show that the nanoparticles on-top layers can be used to enhance the light output of LEDs either by increasing the internal quantum efficiency through surface plasmon coupling or by increasing the light extraction efficiency through near field interaction with the evanescent field induced by the total internal reflection of the light.