Abstract Surface enhanced Raman scattering (SERS) is a surface sensitive technique that is attractive for molecular detection. SERS performance has nanometallic structure dependence however fabrication of a substrate with high sensitivity, uniformity, reproducibility and stability is still one of the most active topics in SERS research. In this study, we report the fabrication of Au-Ag dealloyed nanorod SERS substrates via a co-sputtering technique by oblique angle deposition (OAD) followed by selective chemical etching. Substrates were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle, ultraviolet–visible spectrometry, X-ray diffraction, acid-base titration and Raman spectroscopy. Results showed that the surface roughness increases on the dealloyed substrate compared to the alloy substrate and more gold atoms are available on the surface of the dealloyed substrates for 4-MBA absorption which played a vital role in enhancing the SERS effect. The optimal SERS substrate was achieved by etching in methanol, hydrogen peroxide, and ammonium hydroxide solution for 40 s. The Au-Ag dealloyed substrates exhibited increased SERS enhancement factor in the range of 1.5x106. Long-term stability of the optimal dealloyed substrates was observed over a month of storage time under ambient conditions, superior to the Au-Ag alloyed and Ag only nanorod substrates. In addition, the Au-Ag dealloyed substrates demonstrated uniformity and reproducibility with an acceptable relative standard deviation.

中文翻译：

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通过共溅射技术和选择性化学蚀刻脱合金制备 Au-Ag 纳米棒 SERS 衬底

摘要 表面增强拉曼散射（SERS）是一种对分子检测具有吸引力的表面敏感技术。SERS 性能具有纳米金属结构依赖性，然而制备具有高灵敏度、均匀性、重现性和稳定性的衬底仍然是 SERS 研究中最活跃的课题之一。在这项研究中，我们报告了通过斜角沉积 (OAD) 和选择性化学蚀刻的共溅射技术制造 Au-Ag 脱合金纳米棒 SERS 衬底。通过扫描电子显微镜、X 射线光电子能谱、水接触角、紫外-可见光谱、X 射线衍射、酸碱滴定和拉曼光谱对基材进行表征。结果表明，与合金基体相比，脱合金基体的表面粗糙度增加，脱合金基体表面有更多的金原子可用于 4-MBA 吸收，这在增强 SERS 效应方面起着至关重要的作用。通过在甲醇、过氧化氢和氢氧化铵溶液中蚀刻 40 秒获得最佳 SERS 基板。Au-Ag 脱合金基板在 1.5x106 范围内表现出增加的 SERS 增强因子。在环境条件下超过一个月的储存时间观察到最佳脱合金基材的长期稳定性，优于 Au-Ag 合金和仅 Ag 纳米棒基材。此外，Au-Ag 脱合金基板表现出均匀性和再现性，具有可接受的相对标准偏差。