The Theory of SERS on Dielectrics and Semiconductors

TL;DR

This paper explains the mechanisms behind surface-enhanced Raman scattering (SERS) on dielectric and semiconductor substrates, highlighting the role of electric field enhancement at surface roughness and the influence of dielectric properties.

Contribution

It provides a theoretical framework for understanding SERS on dielectrics and semiconductors, supported by experimental validation.

Findings

Electric field enhancement occurs at surface roughness with small radii or high curvature.

Enhancement strength increases with larger dielectric constant of the substrate.

SERS enhancement on dielectrics and semiconductors is weaker than on metals with similar dielectric constants.

Abstract

It is demonstrated that the reason of SERS on dielectric and semiconductor substrates is the enhancement of the electric field in the regions of the tops of the surface roughness with very small radius, or a very large curvature. The enhancement depends on the dielectric constant of the substrate and is stronger for a larger dielectric constant. It is indicated that the enhancement on dielectrics and semiconductors is weaker than on metals with the same modulus of the dielectric constant. The result obtained is confirmed by experimental data on the enhancement coefficients obtained for various semiconductor and dielectric substrates.