Electromagnetic Modelling of Raman Enhancement from Nanoscale Structures as a Means to Predict the Efficacy of SERS Substrates

The requirement to optimise the balance between signal enhancement and reproducibility in surface enhanced Raman spectroscopy (SERS) is stimulating the development of novel substrates for enhancing Raman signals. This paper describes the application of finite element electromagnetic modelling to predict the Raman enhancement produced from a variety of SERS substrates with differently sized, spaced and shaped morphologies with nanometre dimensions. For the first time, a theoretical comparison between four major generic types of SERS substrate (including metal nanoparticles, structured surfaces, and sharp tips) has been performed and the results are presented and discussed. The results of the modelling are consistent with published experimental data from similar substrates