Photoluminescence Redistribution of InGaN Nanowires Induced by Plasmonic Silver Nanoparticles

Abstract

Hybrid nanostructures based on InGaN nanowires with decorated plasmonic silver nanoparticles are investigated in the present study. It is shown that plasmonic nanoparticles induce the redistribution of room temperature photoluminescence between short-wavelength and long-wavelength peaks of InGaN nanowires. It is defined that short-wavelength maxima decreased by 20%, whereas the long-wavelength maxima increased by 19%. We attribute this phenomenon to the energy transfer and enhancement between the coalesced part of the NWs with 10–13% In content and the tips above with an In content of about 20–23%. A proposed Fröhlich resonance model for silver NPs surrounded by a medium with refractive index of 2.45 and spread 0.1 explains the enhancement effect, whereas the decreasing of the short-wavelength peak is associated with the diffusion of charge carriers between the coalesced part of the NWs and the tips above.

Effect of Plasmonic Ag Nanoparticles on Emission Properties of Planar GaN Nanowires

“…where ε and ε m are the dielectric constant of the metal and the medium, respectively. The effect of the Fröhlich resonance of metal nanoparticles on the optical spectra of photonic structures has been described earlier [34,37,38]. In the general case, as aforementioned, the scattering of spherical particles is described using the Mie theory, which gives the scattering and extinction cross-sections as a sum of the electric and magnetic spherical waves (harmonics).…”

“…The scattering cross-section spectrum is an important quantity because the strength of the electric field localized near the surface of a metal nanoparticle on a semiconductor nanowire is proportional to the scattering cross-section on that nanoparticle. Hence, there is a correlation between a feature in the scattering cross-section spectrum and the PL spectrum of nanowires [28,38]. Below we consider different approaches.…”

“…Note that the calculations for particles in the range of 50-70 nm are not affected by the NP size on the position of the plasmonic resonance. However, if the Ag NP is oxidized, then the resonance condition for a metal particle covered with a dielectric shell is given by the formula [38]:…”

Fröhlich resonance splitting in hybrid GaN nanowire-Ag nanoparticle structures

“…This intensity is directly proportional to the scattering cross-section of the NP. As a result, a direct correlation exists between specific features within the scattering cross-section spectrum and the PL spectrum of NWs [20,32,33].…”

“…Among different metals, silver exhibit high refractive index sensitivity and higher figure of merit [9] and is considered as one of the most important materials for plasmonics that can support a strong surface plasmon at a desired resonance wavelength in a broad spectrum from 300 to 1200 nm [14]. Given the significance of modifying and enhancing spontaneous emissions, ongoing efforts are directed towards exploring diverse semiconductor nanostructures with unique optical properties, ranging from Tamm plasmon photonic crystals and periodic Bragg structures to meso-resonators and hybrid structures [15][16][17][18][19][20].…”