One-side metal-coated pyramidal cantilever tips for highly reproducible tip-enhanced Raman spectroscopy
One-side metal-coated pyramidal cantilever tips for highly reproducible tip-enhanced Raman spectroscopy
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DOI：
10.1088/1361-6528/ab90b6
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发表时间：
2020-08-14
期刊：
影响因子：
3.5
通讯作者：
Verma, Prabhat
中科院分区：
文献类型：
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作者：
Kato, Ryo;Taguchi, Koki;Verma, Prabhat
针尖增强拉曼光谱（TERS）是一种非常有用的纳米尺度化学分析工具，在带隙模式下可以达到亚纳米尺度。使用原子力显微镜（AFM）在间隙模式TERS的金属尖端的位置控制，一个独特的和相关的分析，甚至可以实现在单分子水平。然而，基于AFM的间隙模式TERS的关键问题之一是可靠的和可重复的悬臂金属尖端的制造。在这里，我们提出了一个简单的，具有成本效益的制造方法的金属涂层的AFM为基础的间隙模式TERS通过物理气相沉积技术在一个可重复的方式。我们的plamonic尖端在金字塔形尖端的一侧具有非常光滑的银层，这与常规金属尖端完全不同，后者在其身体上随机排列颗粒状金属结构。重要的是，所有制造的尖端都表现出超过10（4）的相当高的增强因子，这表明我们的等离子体尖端在间隙模式配置中的再现性几乎为100%。间隙模式TERS测量的良好再现性为基于AFM的TERS作为一种强大的分析技术在广泛的领域提供了巨大的希望。
Tip-enhanced Raman spectroscopy (TERS) has been recognized as a useful tool for nanoscale chemical analysis, and it can further reach down to the sub-nanometer scale in the gap-mode configuration. Using an atomic force microscopy (AFM) in gap-mode TERS for position control of a metallic tip, a unique and correlative analysis can be even realized at the single molecule level. However, one of crucial issues in AFM-based gap-mode TERS is the fabrication of reliable and reproducible cantilver metallic tips. Here, we propose a simple, cost-effective fabrication method of metal-coated tips for AFM-based gap-mode TERS by means of the physical vapor deposition technique in a reproducible way. Our plamonic tips have extremely smooth silver layers on one side of the pyramidal tip, which is totally different from the regular metallic tips that hold granular metallic structures randomly arranged on their bodies. Importantly, all fabricated tips exhibited a reasonably high enhancement factor of more than 10(4), which indicates that the reproducibility of our plasmonic tip is virtually 100% in the gap-mode configuration. The excellent reproducibility of gap-mode TERS measurement holds great promise for rendering AFM-based TERS as a powerful analytical technique in a broad range of fields.