Cu₂O_{1- x}-Superlattices Induced Oxygen Vacancy for Localized Surface Plasmon Resonance

Metallic oxide can induce localized surface plasmon resonance (LSPR) through creating vacancies, which effectively achieve high carrier concentrations and offer advantages such as versatility and tunability. However, vacancies are typically created by altering the stoichiometric ratio of elements through doping, and it is challenging to achieve LSPR enhancement in the visible spectral range. Here, we have assembled Cu₂O_1-x-superlattices to induce a high concentration of oxygen vacancies, resulting in LSPR within the visible spectrum. Combining this technique with theoretical models, we have elucidated the mechanism behind the origin of LSPR. We also provide evidence of strong and uniform LSPR exhibited by this structure under visible light. This significantly enhances the electromagnetic field in semiconductor-based surface-enhanced Raman scattering (SERS), with a detection limit concentration reaching 10^-9 M compared to conventional gold nanoparticles (55 nm). Our strategy provides a new perspective and potential for controlling carrier concentration and generating LSPR in metal oxide nanoparticles.