Synergistic antireflection and SERS enhancement in hybrid silicon nanowires by LIL and MACE

This paper presents an innovative approach to fabricating dual-functional hybrid silicon nanowire (SiNW) arrays that demonstrate antireflection and Surface-Enhanced Raman Scattering (SERS) potentials. Three-beam laser interference lithography (TBLIL) is used to create interference fringe patterns on a Si substrate, which serves as a template for subsequent NWs creation. Subsequently, metal-assisted chemical etching (MACE) selectively etched the substrate and stimulated the formation of SiNWs with various aspect ratios. The morphological and optical features of the hybrid SiNWs were characterized by scanning electron microscopy (SEM), finite difference time domain (FDTD), and Raman spectroscopy. The resulting structured surface morphology effectively reduced the reflection losses at various wavelengths. The Raman spectra of rhodamine 6G (R6G) analytes at concentrations of 10^–4 to 10^–8 are examined, indicating that the Raman signals were significantly enhanced and had long-term stability and reliability. The Raman characteristic peaks of R6G were observed at 620, 1361, and 1660 cm⁻¹, which are potentially useful in sensitive chemical sensors.