Structural effects of silver-nanoprism-decorated Si nanowires on surface-enhanced Raman scattering

Abstract

Surface enhanced Raman scattering (SERS) is an important analytical tool for the optochemical detection of molecules. The enhancement is commonly achieved by engineering (i) novel types and morphologies of plasmonic nanomaterials, and (ii) patterned or roughened supporting substrates of high surface area for increased light scattering and molecule adsorption. Si substrates can be easily and reproducibly textured for effective SERS applications. In this work, silver nanoprisms (AgNPr) coated silicon nanowire (SiNWs) of different morphologies have been prepared by metal-assisted chemical etching and tested for SERS detection of R6G dye. By varying the etching time from 5 to 30 min, the nanowires’ lengths increased from 2.4 to 10.5 µm and resulted in a variable topological morphology of the substrates in terms of bundles and valleys. We found that an optimum of 10 min etching time led to the highest SERS enhancement of R6G on AgNPr/SiNWs at 612 cm−1 Raman shift (30× compared to R6G/Si and 2× compared to R6G/AgNPr/Si), with a detection limit comparable to that of state-of-the-art performances (down to 5×10−10 M of R6G). Such an enhancement is attributed to a middle ground between increased overall surface area of SiNWs, and the available bundle tops trapping the AgNPr and R6G molecules.

Ultra-sensitive and fast optical detection of the spike protein of the SARS-CoV-2 using AgNPs/SiNWs nanohybrid based sensors

“…Finally, the SiNWs grown on the Si wafers were washed and dried at ambient atmosphere. The formation of the SiNWs array was prominently evident from the visual observation of black color over the substrate at the end of the preparation process [ 12 , 32 ].…”

“…Among several sophisticated analytical instruments, surface-enhanced Raman spectroscopy (SERS) has proved its effectiveness in terms of unswerving, extreme sensitivity as well as high selectivity for identification of analytes under examination [9] , [10] . The technique has progressively evolved from the basic detection of chemical finger-print of organic molecules towards an alternative bio-analytical tool for the detection of microbes to a greater extent with excellent specificity and reproducibility by tailoring the design of substrates [11] , [12] , [13] . Rapid trace level detection of micro-biological organisms with SERS will ease the spread of their diverse effects on human civilization.…”

Photoelectrocatalytic activity of silicon nanowires decorated with electroless copper nanoparticles and graphene oxide using a plasma jet for removal of methyl orange under visible light

“…Silicon nanowires (Si NWs ) have gained interest in the last few years due to their versatility and properties like absorption, light emission, catalytic activity, and a wide range of applications. Among all its applications, they can be exploited for photocatalysis, [7][8][9][10] solar water splitting, 11,12 detection of molecules, [13][14][15] light trapping, 16,17 reduction of metals, 18 storage and energy conversion, 19 CO 2 reduction, 20,21 hydrogen generation, 22 and many other applications. Moreover, it has been reported that the decoration of silicon nanowires with metallic nanoparticles can enhance their catalytic properties, especially for electron discharging.…”

Surface Functionalization of Graphene Oxide with Polystyrene Sulfonic Acid Brushes to Fabricate Hierarchical Ag and Au Microstructures as SERS Substrates

“…The Raman intensity decreases with decreasing the concentration of R6G from 10 À 6 to 10 À 12 m, and it can clearly identify the main characteristic peaks until the concentration of 10 À 12 m, implying the LOD of R6G on GO-g-PSSA/Ag film is as low as 10 À 11 m. Some of the recently reported Ag-based SERS substrates have same or much higher LOD values compared to our work. [42][43][44] Although, much lesser LOD values (10 À 13 m and 10 À 16 m) are also reported, those works involve some complex synthesis or treatments. [45,46] The plot of Raman intensity of the peak at 613 cm À 1 recorded from GO-g-PSSA/Ag film versus logarithmic concentration of R6G is shown in Figure 6B.…”