Metal catalyzed, CVD-grown silicon nanowires decorated by chemical assembly of closely spaced Ag nanocrystals were modified with the well-known "silver mirror" reaction and investigated as substrates for surface-enhanced Raman (SERS) and hyper-Raman (SEHRS) spectroscopy. Four chromophores were examined: Rhodamine 6G, crystal violet, a cyanine dye, and a cationic donor-acceptor substituted stilbene. After soaking the substrates overnight in 10-4 M aqueous chromophore solutions, all four chromophores gave good-quality SERS spectra in ≤ 60 s using < 1 μW of 458-nm cw laser power, and SEHRS spectra are obtained in ≤ 120 s using < 1 mW of mode-locked 916-nm laser power. Results from this substrate are compared with those on colloidal silver nanoparticles deposited as a film, as well as surfaces grown by the silver mirror reaction.
ASJC Scopus subject areas
- Analytical Chemistry