Surface plasmon coupling dynamics in InGaN/GaN quantum-well structures and radiative efficiency improvement

Abstract

Surface plasmonics from metal nanoparticles have been demonstrated as an effective way of improving the performance of low-efficiency light emitters. However, reducing the inherent losses of the metal nanoparticles remains a challenge. Here we study the enhancement properties by Ag nanoparticles for InGaN/GaN quantum-well structures. By using a thin SiN dielectric layer between Ag and GaN we manage to modify and improve surface plasmon coupling effects, and we attribute this to the improved scattering of the nanoparticles at the quantum-well emission wavelength. The results are interpreted using numerical simulations, where absorption and scattering cross-sections are studied for different sized particles on GaN and GaN/SiN substrates.

Internal quantum efficiency enhancement of GaInN/GaN quantum-well structures using Ag nanoparticles

“…Through numerical calculations we have previously investigated the decay rate enhancement in the plane of the QWs from Ag NPs, and have found that larger NPs exhibit larger enhancement factors for particle sizes up to about 200 nm in diameter. 30 The difference in average Ag NP size between sample B and C explains why the Purcell factor of C is larger than B.…”

“…These effects were previously investigated and it was found that the scattering to absorption ratio is an important characteristic when determining whether Ag NPs can provide efficiency enhancement. 30 The absorption in the NP is the loss channel for the LSP mode, and reducing these losses relative to the scattering can ensure a higher LSP mode radiative efficiency. Despite the matching of the extinction or resonance peak of sample B with the emission wavelength, sample C is expected to have a higher scattering capacity at the emission wavelength due to its larger average Ag NP sizes relative to sample B.…”

“…Despite the matching of the extinction or resonance peak of sample B with the emission wavelength, sample C is expected to have a higher scattering capacity at the emission wavelength due to its larger average Ag NP sizes relative to sample B. 30,33 This is because the scattering-to-absorption ratio of sample C is higher than B due to the larger Ag NPs. As such sample C is scattering dominated and sample A is absorption dominated, while sample B is in between these limits.…”

Coherent and Polarized Random Laser Emissions from Colloidal CdSe/ZnS Quantum Dots Plasmonically Coupled to Ellipsoidal Ag Nanoparticles

“…In this work, we experimentally demonstrate coherent random laser emissions around λ = 643 nm from the CdSe/ZnS QDs with an introduction of ellipsoidal silver nanoparticles (Ag NPs). Although metallic nanoparticles have been intensively studied to enhance the spontaneous emission and luminescence efficiency for various optoelectronic devices, the incorporation of metallic nanoparticles into optical gain medium and the cooperative interaction with the stimulated emissions are rarely reported, especially for the colloidal QDs‐based system. In the previous study, star‐shaped gold nanoparticles are integrated and immersed into colloidal QDs film to provide required optical feedback by inducing plasmonic scattering events.…”

Droplet-induced dot, dot-in-hole, and hole structures in GaGe thin films grown by MOCVD on GaAs substrates

“…23,[29][30][31][32] Recent developments in surface plasmonics and metamaterials have seen many new applications of combining metallic nanoparticles and semiconductors in various configurations to enhance light absorption and/or scattering. [33][34][35][36] For this purpose, both unintentional surface V-shaped defects (i.e., V-pits) and intentionally patterned V-shaped holes in semiconductors have been employed for locating metal dots to enhance their surrounding optical near-field so as to couple into the active regions embedded in the semiconductor structures. 35,37 Here, we demonstrate a novel mechanism for creating Ga droplets on GaGe thin films epitaxially grown by MOCVD on lattice-matched GaAs (100) substrates; by tuning the Ga composition (i.e., via adjusting the flow rate ratio of Ga/Ge precursors) and the growth temperature, dot, dot-in-hole, and hole structures are well created in the GaGe thin films due to the finite solubility of Ga atoms in the crystalline Ge matrix and vice versa.…”