Modulation of Interfacial Band Bending and Enhanced Optical Performance in GaAs/AlGaAs Core–Shell Nanowires with Ag Nanoparticles

One-dimensional GaAs/AlGaAs core–shell nanowires (NWs) have great potential for advanced optoelectronic applications. However, their optical performance is often hindered by interfacial band bending at the core–shell interface. This work presents a new method of modulating the interfacial band structure and enhancing the optical performance by incorporating silver nanoparticles (Ag NPs). GaAs/AlGaAs NW arrays were grown by using molecular beam epitaxy, followed by the deposition of Ag NPs via vacuum thermal evaporation. Spectroscopic analysis shows that the Ag NPs effectively suppress interfacial band bending, as indicated by the disappearance of quasi-type-II transitions, narrower spectral line-widths, and reduced carrier trapping. Photoluminescence measurements rule out surface plasmon resonance (SPR) enhancement and attribute the observed intensity variations to the absorption of Ag NPs and the energy mismatch. Room-temperature random lasing experiments demonstrate that GaAs/AlGaAs NWs with Ag NPs exhibit a significantly lower lasing threshold and a stronger spatial localization. These properties are related to the improved material quality and modulation of the interfacial band bending. These findings highlight the potential of Ag NPs for tailoring interfacial band structures, paving the way for high-performance nanoscale optoelectronics, particularly in lasers.