Hybrid SERS substrates for chemical and biological. sensing

摘要

We present two novel hybrid surface enhanced Raman scattering (SERS) based substrates - the hybrid `nanoline (NL)-nanoparticle (NP)' plasmonic substrates and the `nanofingers inside nanowires' plasmonic substrates. These substrates, which have been fabricated by employing a combination of top-down and bottom-up nanofabrication processes, allow easily achievable sub-5 nm gaps and a possibility of large area fabrication. Theoretical studies were conducted, using Finite Difference Time Domain (FDTD) modelling, to understand the effect of the various geometrical parameters of these substrates on the magnitude of the SERS enhancement and the plasmon resonance tunability. We also discuss the fabrication, characterization and measurement of SERS signals from these substrates.