RESUMO
We achieved significant enhancements in green light emission (550â nm) from InGaN/GaN quantum wells (QWs) by tuning the localized surface plasmon resonance (LSPR) of self-assembled Ag nanoparticles (NPs) through the application of a SiO2 thin film. The LSPR wavelength of Ag NPs was shifted towards shorter wavelengths by 80â nm using a 5â nm SiO2 layer to separate Ag NPs from GaN surface, thereby aligning it effectively with the green region. This strategic placement of Ag NPs and a 5â nm SiO2 film resulted in significant enhancements of photoluminescence (PL) by 15- and 8.8-fold with 5 and 11â nm GaN cap layers, respectively. The LSPR of Ag NPs on a SiO2 thin film facilitated a longer possible distance for the coupling between surface plasmons (SPs) and excitons in a QW. Traditionally, the distance between SPs-generating metal and a QW has been maintained at 10â nm to achieve substantial enhancements. Remarkably, even with a 25â nm cap layer, Ag NPs on a 5â nm SiO2 film boosted PL by 3.1-fold. The enhancements attributable to Ag NPs on SiO2 films were superior, reaching up to 4.8 times greater than those of Ag NPs on GaN surfaces. Additionally, the PL enhancement factors calculated using the finite differential time domain (FDTD) method aligned closely with experimental results.