Plasmonie light-emission enhancement with isolated metal nanoparticles and their coupled arrays

We present a systematic study of the enhancement of radiative efficiency of light-emitting matter achieved by proximity to metal nanoparticles. Our goal is to ascertain the limits of the attainable enhancement. Two separate arrangements of metal nanoparticles are studied, namely isolated particles and an array of particles. The method of analysis is based on the effective mode volume theory. Using the example of an InGaN/GaN quantum-well active region positioned in close proximity to Ag nanospheres, we obtain optimal parameters for the nanoparticles for maximum attainable enhancement. Our results show that while the enhancement due to isolated metal nanoparticles is significant, only modest enhancement can be achieved with an ordered array. We further conclude that a random assembly of isolated particles holds an advantage over the ordered arrays for light-emitting devices of finite area.