A Low-cost, Highly-stable Surface Enhanced Raman Scattering Substrate by Si Nanowire Arrays Decorated with Au Nanoparticles and Au Backplate

Abstract

We present a facile and cost-effective manner to fabricate a highly sensitive and stable surface enhanced Raman scattering (SERS) substrate. First, a silicon nanowire array (SiNWA) is tailored by metal-assisted chemical etching (MaCE) method as a scaffold of the desired SERS substrate. Next, with an oblique angle deposition (OAD) method, optimized gold nanoparticles (AuNPs) are successfully decorated on the surface of the SiNWA. These AuNPs enable a strong localized electric field, providing abundant hot spots to intensify the Raman signals from the targeting molecules. By applying a well-established methodology, Taguchi method, which is invented for designing experiments, the optimized combination of parameters is obtained efficiently. The experimental results are also confirmed by finite-difference time-domain (FDTD) simulation calculations. Besides, a gold metal backplate (AuMBP) is applied to further enhancing the Raman signal intensity. Based on this developed SERS substrate, we demonstrated an enhancement factor (EF) of 1.78 × 106 and a coefficient of variation (CV) of 4.2%. Both EF and CV indicate a highly stable property and the optimized SERS substrate substantially outperform the commercial product. In the end, we also demonstrate a quantitative measurement on practical application of detecting malachite green (MG) with concentration from 10 nM to 100 μM.

Au-covered hollow urchin-like ZnO nanostructures for surface-enhanced Raman scattering sensing

“…4 shows the SERS spectra of thiophenol molecules grafted on the ZnO urchin-like structures covered with 10, 30, and nm of gold for the two excitation wavelengths used here. Thiophenol was selected due to its ability to form self-assembled monolayers (SAMs) via S-Au bonds [45] and the absence of molecular vibrational activity near the selected excitation wavelengths (633 nm and nm). The characteristic vibrational modes of thiophenol molecules (10 -3 M) are well-observed (see refs [46][47][48])…”

Rapid Biochemical Mixture Screening by Three-Dimensional Patterned Multifunctional Substrate with Ultra-Thin Layer Chromatography (UTLC) and Surface Enhanced Raman Scattering (SERS)

“…In addition, an anisotropic etching method 28 – 30 , metal assisted chemical etching (MaCE) was applied with the following steps: 1. Dip the as-prepared Si chips into an electrolyte of hydrogen fluoride (HF) and silver nitrate (AgNO 3 ) with concentrations of 4.6 M and 0.44 M, respectively for 10 s to form a silver network as shown in step (v) 31 . 2.…”

Preparation of ZnO nanoflowers for surface enhance Raman scattering applications

“…Difficulties in controlling size, shape and the distance between nanoparticles lead to limited repeatability Raman results. Another approach is to distribute noble metal nanoparticles on 1D semiconductor nanostructures [2][3][4]. This approach is hoped to provide reproducibility and consistent analysis results.…”