Large-area hole-sphere nanogap platform for high-sensitivity, low-deviation SERS analysis and its applications

The hole-sphere nanogap (HSNG) platform offers a scalable and highly uniform Surface-Enhanced Raman Scattering (SERS) substrate, addressing challenges in signal enhancement and reproducibility. Fabricated through sequential thin film deposition, heat treatment, and wet etching, the HSNG structure achieves signal uniformity below 10% across a 6-inch wafer and an enhancement factor exceeding 108. By precisely tuning nanoparticle size and nanogap distance, the platform optimizes localized surface plasmon resonance (LSPR) for trace-level detection. HSNG demonstrated its versatility in detecting arsenic compounds in water at concentrations down to 1 ppm, explosive vapors such as TNT at atmosphere pressure, and contaminants like melamine and pesticides in food matrices. Its high sensitivity, reproducibility, and scalability make HSNG a promising candidate for field-deployable sensing systems in environmental, security, and food safety applications.