Surprisingly Long-Range Surface-Enhanced Raman Scattering (SERS) on Au-Ni Multisegmented Nanowires

摘要

An appropriate wavelength of light impinging on a noble metal nanostructure can cause the conduction-band electrons to oscillate collectively, resulting in localized surface plasmon resonance (LSPR) excitation. This process generates enhanced electromagnetic (EM) fields at the surface of the nanostructure that can be several orders of magnitude larger than the incident optical excitation fields, leading to many types of surface-enhanced phenomena, including surface-enhanced Raman scattering (SERS). SERS has been extensively studied for several decades, and it is often described as a near-field phenomenon that occurs when the Raman-active molecules are in proximity to the surface of the nanostructure, as the enhanced EM fields decay rapidly with distance from its surface. The decay lengths have been reported to be in the range of a few nanometers and depend on the size, shape, and composition of the nanostructure.