Charge transfer study for semiconductor and semiconductor/ metal composites based on surface‐enhanced Raman scattering

Abstract

With the development of the surface‐enhanced Raman scattering (SERS) technique, new multipurpose and multiperformance SERS‐active substrates have been developed. Semiconductor and semiconductor/metal composites show versatility and SERS activity for theoretical and practical applications. Semiconductor‐based SERS substrates with different microstructures, materials and compositions have been prepared to explore the enhancement effect on Raman signals. The discovery of the SERS enhancement effect of semiconductors makes up for the gap that SERS development is limited to metal‐based materials. Semiconductor/metal composite substrates have established preparation technology that is compatible with the characteristics of different materials to form a stable and solid substrate that can regulate the SERS enhancement mechanism. These composites establish a good model for the theoretical research of SERS, which is of great significance to explore its enhancement mechanism. In this review, various semiconductor materials are introduced as SERS‐active substrates. Versatile applications of semiconductor‐based SERS and its enhancement mechanism are also presented.

Semiconductor-based surface enhanced Raman scattering (SERS): from active materials to performance improvement

“…the energy level distribution of semiconductor substrates to enhance the charge transfer process. Charge transfer in a semiconductor-molecule system generally involves the following pathways 11,[30][31][32] : (1) Molecule HOMO-to-CB; (2) Charge transfer complex-to-CB; (3) VB-to-molecule LUMO; (4) VB-tosurface state-to-molecule LUMO; and (5) CB-to-molecule HOMO. Since some articles have discussed the above charge transfer process in depth, 11,12,33 this review will not discuss it in detail.…”

Human metabolite detection by surface-enhanced Raman spectroscopy

“…Surface-enhanced Raman spectroscopy (SERS) is an ultra-sensitive and highly specific optical detection technique, benefited from the molecular “fingerprint” of Raman spectrum and the enormous signal enhancement (down to a single-molecule level) by plasmonic nanomaterials [ 28 , 29 ]. The applications of SERS in chemistry, biology and medicine have been widely reported [ [30] , [31] , [32] ].…”

TiO2 Thickness-Dependent Charge Transfer in an Ordered Ag/TiO2/Ni Nanopillar Arrays Based on Surface-Enhanced Raman Scattering

“…It is commonly accepted that electromagnetic enhancement (EM) and chemical enhancement (CM) contribute to the satisfactory enhancement of SERS. EM is mainly attributed to the collective oscillation of free electrons on the plasmonic metal surface under the excitation of incident light to generate surface plasmon resonance (SPR), which greatly enhances the strength of the electromagnetic field on the metal surface [ 5 , 6 ]. Previous studies proved that SPR depends to a large extent on parameters such as the morphology, size, thickness and spacing of plasmonic materials, while the relationship between parameters regulation of metal and SERS performance has also been widely discussed [ 7 , 8 ].…”