Plasmonic coupling in GaN films by Au and Ag Nanoparticles: Synthesis and characterization

The integration of metallic nanostructures with compound semiconductors offers a powerful platform to investigate plasmon - exciton interactions, being of great interest for both fundamental studies and technological applications [1]. In this work, we focus on gallium nitride (GaN) thin films functionalized with gold (AuNPs) and silver (AgNPs) nanoparticles in order to analyze their optical and surface properties [2]. For the synthesis of AuNPs, a factorial Design of Experiments was implemented , allowing us to evaluate the influence of different synthesis parameters on nanoparticle formation. DLS analysis revealed particle size distributions ranging from 25 to 73 nm.

In the case of AgNPs, a custom-built electrolysis system was employed to ensure reproducibility and control over particle formation. DLS characterization indicated sizes between 15 and 20 nm, demonstrating a narrower distribution compared to AuNPs. The optical behavior of both nanoparticle systems was further investigated by UV-Vis spectroscopy. Characteristic plasmon resonance bands were observed at 520 nm for AuNPs and 420 nm for AgNPs, in agreement with values typically reported for spherical nanoparticles in this size range.

Finally, GaN films decorated with these metallic nanoparticles were examined to assess the combined optical response and surface modification. A noticeable reduction in the blue defect-related luminescence of GaN at 420 nm was observed upon the incorporation of gold nanoparticles, attributed to localized surface plasmon resonance effects.

[1] "Surface plasmon coupling dynamics in InGaN/GaN quantum-well structures and radiative efficiency improvement" 2014.

[2] Liu et al. "Enhancement light trapping in InGaN thin films with Al nanoparticules" 2021.