【摘要】 探针的质量是实现高信号增益以及高分辨针尖增强拉曼实验的关键.本文报道了一种通过在原子尺度上改变探针尖端形貌来可控制备针尖增强拉曼活性探针的方法,并提出了两个重要的准则来原位判断用于针尖增强拉曼实验探针的针尖增强拉曼活性.一个判据是利用第一镜像势峰位向低能量的移动来监测远场入射激光与近场等离激元之间的耦合,另一个判据是根据与探针尖端原子级突起相关的低波数拉曼峰的出现来判断从近场到远场辐射的耦合效率.该研究为在目标分子和其他材料上进行真正的针尖增强拉曼实验之前快速制备和判断针尖增强拉曼活性探针提供了一种有效的方法,有望为针尖增强拉曼等探针增强光谱技术的发展提供帮助.更多还原

【Abstract】 The quality of the scanning tip is crucial for tip-enhanced Raman spectroscopy(TERS) experiments towards large signal enhancement and high spatial resolution. In this work, we report a controllable fabrication method to prepare TERS-active tips by modifying the tip apex at the atomic scale, and propose two important criteria to in-situ judge the tip’s TERS activity for tip-enhanced Raman measurements. One criterion is based on the downshift of the first image potential state to monitor the coupling between the far-field incident laser and near-field plasmon;the other is based on the appearance of the low-wavenumber Raman peaks associated with an atomistic protrusion at the tip apex to judge the coupling efficiency of emissions from the near field to the far field. This work provides an effective method to quickly fabricate and judge TERS-active tips before real TERS experiments on target molecules and other materials, which is believed to be instrumental for the development of TERS and other tip-enhanced spectroscopic techniques.更多还原