Surface Plasmon Coupled Light-emitting Diode

In this presentation, we first review our theoretical/numerical study results on the coupling behavior between a radiating dipole and the surface plasmon (SP) induced on a metal nanostructure, including an embedded Ag nanoparticle (NP), a surface Ag NP, and an Ag protrusion. In the case of surface Ag NP, the effects of adding a dielectric interlayer are investigated. From the numerical results, we can summarize a few important features of SP coupling behaviors, which are useful for designing an SP coupled light-emitting diode (LED). Then, a few important implementations of SP coupled LED with different metal nanostructures are discussed. In particular, its functions of enhancing the internal quantum efficiency, suppressing the efficiency droop effect, and increasing the modulation bandwidth of an LED are demonstrated. Next, we discuss our recent efforts of enhancing the emission efficiency of a deep-UV LED, including the preliminary results of numerical and experimental studies on the enhancement of TE-polarized emission, suppression of TM-polarized emission (low light extraction), and minimization of p-GaN absorption. Currently, a p-GaN layer is needed at the top of an AlGaN-based deep-UV LED for increasing the current injection efficiency. However, the p-GaN layer can absorb deep-UV emission. This effect needs to be minimized for increasing the light extraction efficiency of a deep-UV LED.