Defect engineering in semiconductor-based SERS

Abstract

Semiconductor-based surface enhanced Raman spectroscopy (SERS) platforms take advantage of the multifaceted tunability of semiconductor materials to realize specialized sensing demands in a wide range of applications. However, until quite...

Emerging SERS biosensors for the analysis of cells and extracellular vesicles

“…The combination of the two mechanisms, taking advantage of the synergic effect between the two well-known mechanisms, in developing SERS substrates has been one of the hot topics in this research area. While surface defect-engineered semi-conductors have been used as potential SERS substrates for some biomedical applications, [57][58][59] it seems that the application of semiconductor nanomaterials in bioanalysis needs further investigation to solve the practical challenges that researchers face in biomedical applications, in particular in the analysis of cells and extracellular vesicles. Therefore, the combination of noble metal nanostructures and semiconductor nanomaterials has received tremendous attention in the design of SERS substrates with stronger SERS effect compared with noble metal-based substrates or semiconductor-based substrates alone.…”

Application of two-dimensional layered materials in surface-enhanced Raman spectroscopy (SERS)

“…By changing the type and concentration of dopants, the inherent crystal, electronic structure and surface properties of the host material can be modulated. 33 With regard to 2D materials, the strategy of introducing defects by the anionic doping of non-metallic impurities has been widely studied. 34,35 Nitrogen is a common kind of reducing dopant, and the substrate materials can be doped in an ammonia or N 2 atmosphere.…”

“…23 Through defect engineering, the energy band structure, surface properties, and density of states (DOS) of SERS substrates would be altered. As a consequence, the substrate materials are endowed with stronger light trapping ability, better surface interaction, or higher CT efficiency, 24 which contribute to the improved SERS performances of 2D substrates. In this section, we will mainly discuss vacancy design and chemical doping strategies to introduce defects and interpret their effects on SERS properties of substrate materials.…”

“…By changing the type and concentration of dopants, the inherent crystal, electronic structure and surface properties of the host material can be modulated. 33…”

Understanding of chiral site-dependent enantioselective identification on a plasmon-free semiconductor based SERS substrate

“…In principle, the SERS effect is mainly attributed to two mechanisms: (i) strong electromagnetic mechanism (EM) induced by surface plasmon resonance (SPR) and (ii) chemical mechanism (CM) induced by dipole-dipole interactions or charge-transfer resonances between the SERS substrates and probe molecules. [18][19][20][21][22][23][24] Traditionally, owing to the excellent SPR effect, noble metals (Au, Ag, and Cu) have been widely used as substrate materials for SERS with a detection limit as low as 10 À10 M. On the other hand, because of a large number of structural defects, modulated surface sites, and layer-number-dependent bandgap, twodimensional (2D) semiconductor nanosheets (TiO 2 , MoS 2 , ZnO, and WO 3 ) have been discovered as alternatives to noblemetal-based SERS substrates. [25][26][27][28][29] Nevertheless, besides the poor stability of ultrathin materials, the reproducibility of preparing a uniform distribution on carrier surfaces is another challenge for the practical applications of these nanosheet-like semiconductors in SERS.…”