The impact of physical properties of tip and substrate on electric field enhancement in tip-enhanced Raman spectroscopy (TERS)

In this paper, the finite difference time domain (FDTD) method is used to estimate the intensity and distribution of localized electric field enhancement in tip-enhanced Raman spectroscopy (TERS) in the vicinity of a conical tip with a diameter of 10 nm. While comparing the enhancement of electric field in two configurations with and without substrate, the effect of using different tip materials in the vicinity of the substrate and also the effect of different thin film coatings on the tip in the amount of electric field enhancement have been investigated. Tips in TERS systems are made of materials such as gold, silver, aluminum, copper, and silicon, as well as a combination of these materials as a coating. Our simulation results can be used to predict the intensity and distribution of a localized electric field enhancement using a suitable geometric and physical structure design for the experimental implementation of TERS.