Tip-enhanced Raman spectroscopy

As the "fingerprint" spectrum of substances, surface-enhanced Raman scattering (SERS) has extremely high sensitivity. It can detect the molecular traits on the metal surface and reflect the internal structure information of the substance. It is an excellent surface spectroscopy technology. Nevertheless, SERS substrates rely on roughened substrates and nanoparticles of appropriate size, making it hard to use SERS technology to study smooth surface materials or substrates and molecules that do not have SERS active. With the maturity of scanning probe microscopy (SPM) technology, the tip-enhanced Raman spectroscopy (TERS) combining SPM and Raman spectroscopy technology has solved the typical problems in SERS well. Based on the TERS metal tip structure, the spatial detection resolution can be significantly improved, and the research scale can be raised to the single-molecule level. With the rapid development of TERS technology, detection equipment constructed with the help of different types of SPM-TERS systems, metal tip structures, and enhanced modes are used in bioimaging, medical detection, etc. We recognize that it is necessary to provide some new TERS research results. In this review, we initially reviewed the mechanism and structure of TERS. Subsequently, we introduced different novel SPM-TERS systems. Finally, we summarized the research on the tip, gap, and other characteristics of the TERS system and related applications.