The following research paper concerns the analysis and characterisation of commercially available surface-enhanced Raman scattering (SERS) substrates. SERS has long been a potentially very powerful method with a great deal of interest around it; however, there are still many obstacles which do not allow SERS to be easily applied to real-world detection and analysis problems. As such, research around the various types of substrates is ongoing, in the hope of streamlining and improving the Raman enhancement mechanism. Scanning electron microscope images were obtained for each of the three substrates, and their features and scales were described. Enhanced Raman spectra for Rhodamine B were obtained for a range of concentrations using each of the three substrates, and, in addition, surface enhancement maps are presented. Enhancement factors were calculated for the 1358 cm⁻¹ peak of Rhodamine B. Complementing the experimental work, theoretical FEM modelling in COMSOL Multiphysics was performed, with the resulting calculations yielding an enhancement prediction adequately accurate to the real substrates.

This article presents an examination of well-controlled patterns created using a Ga⁺-based focused ion beam (FIB) on glass, while silicon substrates were used to evaluate the FIB performance by its achievable feature size versus time constraints. The pattern creation on glass was developed with the aim of studying potential surface-enhanced Raman spectroscopy (SERS) applications. Furthermore, the FIB was used to create dimer systems of periodically and randomly positioned dumbbell-shaped pits on the glass (each dimer occupies an area of 203 × 87 nm²). By following the bitmap pattern files, the FIB ensured there was 3000 dimer fabrication over a 20 × 20 μm² large area, with a pit size and position variation below 10 nm. The article highlights that FIB can be used for precise large-area nano-fabrication. The gold nanoparticle dimers were formed on the prepatterned surface via capillary force-assisted deposition. The fabricated nanostructures were tested in SERS measurements. The enhancement factor for Rhodamine B molecule reached ~10⁵, demonstrating the potential application of the method to create nanostructures in the sensor domain.

In this study, we report the fabrication and characterization of silver nanoparticle-doped zinc oxide tetrapod substrates used for surface-enhanced Raman scattering to detect rhodamine B. Prior to this, silver nanoparticle-doped zinc oxide tetrapods were synthesized using the solar physical vapor deposition method. Subsequently, silver-doped zinc oxide tetrapods were applied onto silicon wafers via the droplet evaporation process. The surface-enhanced Raman scattering activity of the silver nanoparticle-doped zinc oxide tetrapod substrate was evaluated by detecting rhodamine B using Raman spectroscopy. Our results demonstrate that the silver nanoparticle-doped zinc oxide tetrapod substrate exhibits surface-enhanced Raman scattering activity and can detect rhodamine B at concentrations as low as 3 μg/mL. This study suggests that silver nanoparticle-doped zinc oxide tetrapod substrates have potential as surface-enhanced Raman scattering platforms as well as potential for the detection of biomolecules.

This study explores a novel approach to surface-enhanced Raman scattering (SERS) substrate fabrication through the heat-induced fragmentation of gold nanowires (Au NWs) and its impact on gold nanoparticle adhesion/static friction using atomic force microscopy manipulations. Controlled heating experiments and scanning electron microscopy measurements reveal significant structural transformations, with NWs transitioning into nanospheres or nanorods in a patterned fashion at elevated temperatures. These morphological changes lead to enhanced Raman signals, particularly demonstrated in the case of Rhodamine B molecules. The results underscore the critical role of NW shape modifications in augmenting the SERS effect, shedding light on a cost-effective and reliable method for producing SERS substrates.

In this study, Mg_1-xZn_xO solid solutions are studied by modelling lattice dynamics, using the methods of classical molecular dynamics. These time-efficient methods are of great interest since they allow using large crystallic structures, which reduce artificial defect periodicity. The main program used is General Utility Lattice Program (GULP). The Buckingham potential is used for modelling interatomic forces. The parameters for this potential are found for different effective ionic charges by using lattice parameters and vibrational frequencies obtained from ab initio calculations performed in the program CRYSTAL14. With these potentials, the dispersion relations and densities of states have been calculated for MgO, ZnO and Mg_1-xZn_xO. Calculations have been made for different Mg and Zn contents in the wurtzite and cubic phase solid solutions, respectively, using the supercell method and a large number of Brillouin zone sampling points. New interatomic potentials for interactions Mg-O, O-O, Zn-O have been obtained. These potential parameters have been verified and the phonon dispersion curves and DOS for MgO and ZnO utilising these potential parameters have been compared to other studies, both experimental and theoretical. By adding more Zn in the cubic phase (c-MgO) solution, no local vibrational modes are observed; however, there is a clear spectral widening and a noticeable change in the low frequency region (100–300 cm⁻¹) of the DOS. Adding more Mg in wurtzite phase (w-ZnO) solution, on the other hand, results in local vibrational modes in the mid (350 cm⁻¹) and high frequency (650 cm⁻¹) regions.