Abstract
Silver nanoparticles (AgNPs) have been reduced onto porous silicon (PSi) surface in a simple immersion plating bath. Here, PSi with average pore size of similar to 30 nm was used as both a mechanical support and a mild reducing agent. AgNPs-meso-PSi hybrid structures exhibit a highly sensitive and reproducible surface-enhanced Raman scattering (SERS) response. A detectable concentration as low as 100 pM of crystal violet has been achieved with an enhancement factor (EF) of 1.3 x 10(6). No aging effect was observed for the current substrates after storing in air for three weeks. The large EF is essentially attributed to a combination of electromagnetic enhancement and charge transfer mechanism. (C) 2015 Elsevier B.V. All rights reserved.