Resistivity dependence on nanostructure formation in picosecond ablation of silicon and SERS-based sensing applications

We report on the influence of resistivity in picosecond (ps) laser ablation of silicon (Si) leading to the formation of diverse surface micro- and nanostructures. Subsequently, we investigated their potential in sensing applications based on the surface enhanced Raman scattering (SERS) technique. The varying resistivity ( ρ 1 : 1–10 Ω cm, ρ 2 : 0.01–0.02 Ω cm, ρ 3 : 0.001–0.005 Ω cm) Si wafers were subjected to cross patterned ps laser ablation in ambient air. Ladder-like microstructures embedded with numerous nano growths were formed on low resistivity Si ( ρ 3 ) while similar micro- and nanostructures were observed on higher resistivity Si ( ρ 2 < ρ 1 ). The structures were non-plasmonic and anti-reflecting in nature with an optical reflectance of