ABSTRACT
We first introduce the basic concept of surface plasmon (SP) coupling with a light emitter or radiating dipole for enhancing its emission efficiency and review some of the past implementations of SP-coupled GaN-based light-emitting diode (LED). Then, the SP resonance behaviors and their potential applications to InGaN/ GaN quantum well (QW) coupling for enhancing LED emission efficiency of three metal nanostructures are discussed, including surface metal nanoparticles (NPs), embedded metal NPs in GaN, and metal nanodisks penetrating into GaN. With a surface metal NP distribution, we demonstrate the QW emission enhancement when the emission wavelength of the QWs beneath roughly coincides with the SP resonance wavelength. The SP resonance wavelength
can be controlled to fall into the green range by designing the NP size. Although the embedded metal NPs in GaN can become closer to the QWs for enhancing the coupling strength, their SP resonance wavelengths are always longer than the green range so that this technique is not suitable for the application to LEDs in the blue and green ranges. Finally, the experimental results of SP resonance features of metal nanodisks penetrating into GaN are illustrated. Certain features can be used for coupling with the green-emitting QWs to enhance their emission efficiency.
