Abstract
We utilized colloidal gold nanocrystals of different shapes (triangular and hexagonal plates, nanorods, and nanoparticles), a self-assembled gold nanoparticle superlattice, and a sputtered gold film to investigate the plasmon-coupling effects on the photoluminescence (PL) from a red-emitting InGaN film. We observed a strong local enhancement (about 1 order of magnitude) of PL intensity at the gold nanocrystal plate covered regions on the InGaN film. In addition, PL intensity spatial distributions were observed for both gold triangular and hexagonal plates deposited on the InGaN film. The acquired distributions could be used to map the plasmonic local density of states on individual nanocrystal plates in the far-field. Furthermore, by comparing scattering and extinction spectra of various gold nanostructures, a self-assembled gold nanoparticle superlattice, and sputtered gold film with the PL spectra in the corresponding InGaN-gold hybrid systems, we have found a consistent occurrence of luminescence enhancement or quenching, depending on the outcoupling efficiency of plasmons into photons in the far-field. © 2010 American Chemical Society.