Plasmonically-Enhanced Emission from an Inverted GaN Light Emitting Diode

TL;DR

This paper demonstrates that dispersing silver nanoparticles on an inverted GaN LED surface enhances its near-bandedge emission through plasmonic coupling, improving exciton decay and light extraction.

Contribution

It introduces a novel inverted LED design with a thin n++ AlGaN top contact that enables plasmonic enhancement of emission via surface nanoparticles.

Findings

Significant increase in emission intensity due to plasmonic coupling.

Enhanced exciton decay rate observed with nanoparticle dispersion.

Proximity of quantum well to nanoparticles enables efficient energy transfer.

Abstract

Silver nanoparticles dispersed on the surface of an inverted GaN LED were found to plasmonically enhance the near-bandedge emission. The resonant surface plasmon coupling led to a significant enhancement in the exciton decay rate and the ensemble of nanoparticles provided a mechanism to scatter the coupled energy as free space radiation. The inverted LED structure employed a tunnel junction to avoid the standard thick p+ GaN current spreading contact layer. In contrast to a standard design, the top contact was a thin n++ AlGaN layer, which brought the quantum well into the fringing field of the silver nanoparticles. This proximity allowed the excitons induced within the quantum well to couple to the surface plasmons, which in turn led to the enhanced band edge emission from the LED.