Construction of Ag/Au bimetallic alloying nanoparticles on GaN films for high-performance SERS substrate, and modification of defect states

Most frequently, pure Ag or Au nanoparticles were used to decorate on GaN-based substrates; however, studies of Ag-Au bimetallic nanoparticles with exceptional optical and plasmonic capabilities are rare. In this study, we present a novel method for creating hybrid Ag-Au NPs/GaN materials, which were discovered to be highly suppressive in the broadband defect emission candidate and high-performance surface-enhanced Raman scattering (SERS) substrates. When the annealing temperature increased from 450 to 650 °C, the average size of Ag nanoparticles reduced from 300 to 50 nm, respectively. Subsequently, enhancing the Raman intensity due to increasing hot spots. The as-fabricated SERS substrate shows a high sensitivity with a wide detection range of 1.0 × 10− 6 – 1.0 × 10− 12 mol L− 1. Furthermore, using the resonance effect between the surface plasmon of Ag-Au NPs and defect emission, the defects states can be suppressed and converted to beneficial excitonic emission. These findings show that Ag-Au bimetallic are a promising candidate for improving optical and trace analyses detection.