In the realm of molecular detection, the surface-enhanced Raman scattering (SERS) technique has garnered increasing attention due to its rapid detection, high sensitivity, and non-destructive characteristics. However, conventional rigid SERS substrates are either costly to fabricate and challenging to prepare over a large area, or they exhibit poor uniformity and repeatability, making them unsuitable for inspecting curved object surfaces. In this work, we present a flexible SERS substrate with high sensitivity as well as good uniformity and repeatability. First, the flexible polydimethylsiloxane (PDMS) substrate is manually formulated and cured. SiO₂/Ag layer on the substrate can be obtained in a single process by using ion beam sputtering. Then, reactive ion etching is used to etch the upper SiO₂ layer of the film, which directly leads to the desired densely packed nanostructure. Finally, a layer of precious metal is deposited on the densely packed nanostructure by thermal evaporation. In our proposed system, the densely packed nanostructure obtained by etching the SiO₂ layer directly determines the SERS ability of the substrate. The bottom layer of silver mirror can reflect the penetrative incident light, the spacer layer of SiO₂ and the top layer of silver thin film can further localize the light in the system, which can realize the excellent absorption of Raman laser light, thus enhancing SERS ability. In the tests, the prepared substrates show excellent SERS performance in detecting crystalline violet with a detection limit of 10⁻¹¹ M. The development of this SERS substrate is anticipated to offer a highly effective and convenient method for molecular substance detection.

中文翻译：

---

反应离子刻蚀制备的高性能、大面积柔性SERS基底用于分子检测

在分子检测领域，表面增强拉曼散射（SERS）技术因其检测速度快、灵敏度高、无损等特点而受到越来越多的关注。然而，传统的刚性 SERS 基底要么制造成本高，并且在大面积上制备具有挑战性，要么表现出较差的均匀性和可重复性，使得它们不适合检查弯曲物体表面。在这项工作中，我们提出了一种具有高灵敏度以及良好均匀性和重复性的柔性 SERS 基底。首先，手动配制并固化柔性聚二甲基硅氧烷 (PDMS) 基材。可以通过使用离子束溅射在单一工艺中获得衬底上的SiO ₂ /Ag层。然后，使用反应离子蚀刻来蚀刻薄膜的上SiO ₂层，这直接导致所需的致密纳米结构。最后，通过热蒸发在致密纳米结构上沉积一层贵金属。在我们提出的系统中，通过蚀刻SiO ₂层获得的致密纳米结构直接决定了基底的SERS能力。底层银镜可以反射穿透的入射光，SiO ₂间隔层和顶层银薄膜可以进一步将光在系统中局域化，从而实现拉曼激光的优异吸收，从而增强SERS能力。测试中，所制备的基底在检测结晶紫方面表现出优异的SERS性能，检测限为10 ^-11 M。该SERS基底的开发有望为分子物质检测提供一种高效、便捷的方法。