Spatially resolved study of InGaN photoluminescence enhancement by single Ag nanoparticles

Spatially resolved photoluminescence (PL) of an InGaN/GaN multiple quantum well (QW) structure covered by Ag nanoparticles (NPs) is studied using confocal microscopy. Up to fourfold enhancement of PL intensity due to the coupling of the QWs with localized surface plasmons (LSPs) induced on single Ag NPs is demonstrated. The enhancement is accompanied by a redshift of the PL spectral peak position towards the LSP resonance wavelength. The correlation between PL intensity and spectral position indicates that the enhancement is stronger in the sample areas emitting at wavelengths that are a better match with the LSP resonance wavelength. The enhancement of light emission and extraction facilitated by photon coupling with LSP in a single Ag NP is demonstrated. (paper)