In this work, we propose simple and inexpensive methods to prepare micro/nano hierarchical Surface-Enhanced Raman Scattering (SERS) substrates, in which pyramid structure is created by using anisotropic wet etching of a silicon wafer and a silver thin film is deposited on these pyramid arrays by thermal evaporation. The ensemble is then annealed at 450 °C for 2 hours to form silver nanoparticles (AgNPs). The sizes and density of the pyramids and AgNPs are optimized mainly by changing the etching temperature (60–80 °C), the thickness of the Ag-film (15–45 nm) and etching time (3–10 min). The ultraviolet visible (UV-Vis) absorbance spectra show that the AgNPs formed with the 30 nm-thick film exhibit the strongest plasmonic effect. Under these conditions, the spherical AgNPs with sizes of 42–48 nm are densely distributed on the silicon micro-pyramid array. The obtained SERS signal is the strongest at the pyramid base-edge size of 7–10 μm. The enhancement factor obtained from the abamectin probe molecules is as high as 1 × 10⁶ and the SERS substrates enable the detection of abamectin concentrations as low as 5.7 × 10⁻⁹ M. Therefore, this work provides a novel SERS substrate structure that has a high potential for use in medicine and biotechnology or as a food security sensor.

中文翻译：

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基于Si金字塔结构和银纳米粒子制备高性能SERS衬底的最佳制造参数

在这项工作中，我们提出了简单且廉价的方法来制备微/纳米分级表面增强拉曼散射 (SERS) 基板，其中金字塔结构是通过使用硅晶片的各向异性湿法蚀刻来创建的，并在这些基板上沉积银薄膜。金字塔阵列通过热蒸发。然后将整体在 450 °C 下退火 2 小时以形成银纳米粒子 (AgNPs)。金字塔和 AgNPs 的尺寸和密度主要通过改变蚀刻温度 (60-80 °C)、Ag 膜的厚度 (15-45 nm) 和蚀刻时间 (3-10 min) 来优化。紫外可见 (UV-Vis) 吸收光谱表明，由 30 nm 厚的薄膜形成的 AgNPs 表现出最强的等离子体效应。在这些条件下，尺寸为 42-48 nm 的球形 AgNPs 密集分布在硅微金字塔阵列上。获得的 SERS 信号在 7-10 μm 的金字塔底边尺寸处最强。从阿维菌素探针分子获得的增强因子高达 1 × 10⁶和 SERS 底物能够检测低至 5.7 × 10 ^-9 M 的阿维菌素浓度。因此，这项工作提供了一种新的 SERS 底物结构，在医学和生物技术或食品安全传感器中具有很高的应用潜力。