Fabrication of surface metal nanoparticles and their induced surface plasmon coupling withsubsurface InGaN/GaN quantum wells

Abstract

Based on the fabrication of Ag nanoparticles (NPs) with controlled geometry andsurface density on an InGaN/GaN quantum well (QW) epitaxial structure, whichcontains indium-rich nano-clusters for producing localized states and free-carrier(delocalized) states in the QWs, and the characterization of their localized surfaceplasmon (LSP) coupling behavior with the carriers in the QWs, the interplaybehavior of LSP coupling with carrier delocalization in the QWs is demonstrated.By using the polystyrene nanosphere lithography technique with an appropriatenanosphere size and adjusting the post-fabrication thermal annealing condition, theinduced LSP resonance wavelength of the fabricated Ag NPs on the QW samplecan match the QW emission wavelength for generating the coherent couplingbetween the carriers in the QWs and the induced LSP. The coupling leads to theenhancement of radiative recombination rate in the QWs and results in increasedphotoluminescence (PL) intensity, red-shifted PL spectrum, reduced PL decay time,and enhanced internal quantum efficiency. It is found that the observed effectsare mainly due to the LSP coupling with the delocalized carriers in the QWs.