Improving hot-spot intensity is a key issue in surface-enhanced Raman scattering (SERS). The bowtie nanoantenna (BNA) is an effective device used to concentrate light energy into a nanoscale volume and produce strong hot spots. Nanosphere lithography (NSL) is a large-area and low-cost technique to produce BNA arrays; however, the SERS activity of NSL-fabricated BNAs is limited. In this paper, we present a simple method to improve the SERS activity of conventional NSL-fabricated BNAs by modifying their geometry. The new configuration is termed "silver-coated elevated bowtie nanoantenna" (SCEBNA). SCEBNAs perform intensive near-field enhancement in the gap cavities owing to the integrated contribution of the "lightning rod" effect, resonance coupling, and the formation of the plasmonic Fabry–Pérot cavity. Experimental measurements and finite-difference time-domain simulations revealed that the hot-spot intensity and the substrate enhancement factor can be optimized by adjusting the silver thickness. The optimal sample has the capability of trace-amount detection with fine reproducibility.

Close-packed Ag pyramidal arrays have been fabricated by using inverted pyramidal pits on Si as a template and used to generate plentiful and homogeneous surface-enhanced Raman scattering (SERS) hot sites. The sharp nanotip and the four edges of the Ag pyramid result in strong electromagnetic field enhancement with an average enhancement factor (EF) of 2.84 × 10⁷. Moreover, the features of the close-packed Ag pyramidal array can be well controlled, which allows SERS substrates with good reproducibility to be obtained. The relative standard deviation (RSD) was lower than 8.78% both across a single substrate and different batches of substrates.

Corrugated silicon nanocone (SiNC) arrays have been fabricated on a silicon wafer by two polystyrene-sphere-monolayer-masked etching steps in order to create high-performance antireflective coatings. The reflectance was reduced from above 35% to less than 0.7% in the range 400–1050 nm, and it remained below 0.5% at incidence angles up to 70° at 632.8 nm for both s- and p-polarized light. The fluorinated corrugated SiNC array surface exhibits superhydrophobic properties with a water contact angle of 164°.