Surface-enhanced Raman Scattering (SERS) Effect of Hexagonally Arranged Gold Nanoparticle Array with 29-nm Particles and 23-nm Gaps Using Liquid-crystalline Block-copolymer Template

A hexagonally arranged gold nanoparticle array with a particle size of 29 nm and gap of 23 nm was fabricated on a silicon wafer substrate through the block-copolymer templating method. Its molecular sensing ability was examined on the basis of surface-enhanced Raman scattering (SERS). With 4-sulfanylpyridine (4-Spy) used as a target molecule, the SERS enhancement factor (EF) for this array was 7.0 × 104. A linear relationship between the SERS signal and the amount of 4-Spy was obtained, with a dynamic range of four orders of magnitude. The highly reproducible SERS sensing originates from the well-ordered gold nanoparticle arrangement over the whole substrate.