Time-Resolved Tunneling Electron-Induced Anti-Stokes Raman Spectroscopy of Interface Aggregate

本项目旨在提高拉曼光谱和发光光谱的空间分辨率。在石墨或氧化铟锡板表面吸附了碳纳米管、金-金属纳米三角形、分子聚集体等多种样品。用于这些测量的仪器是在实验室设计和制造的。采用电化学刻蚀银/铜合金线或在电化学磨尖的钨丝上化学涂覆银金属制成隧道探针。我们发现，当测量纳米管时，拉曼光谱的空间分辨率提高到几十纳米的范围内；然而，地形图像并不总是与光谱图像相对应。这种偏差被认为是由于等离子体增强发生的空间和隧道电流流动的不同。镉夜曲量子点在氧化铟锡板上的光致发光与量子点与隧道探针之间的距离密切相关，具有纳米级的发光精度。在氧化铟锡表面吸附的金纳米三角形为扫描隧道显微镜提供了良好的原子平面，并为反式光学显微镜提供了半透明的衬底。此外，我们发现金纳米三角形的某些部分只有在接近隧道探针时才会发光。这些结果有望为纳米领域的高空间分辨率光谱学的发展做出贡献。

This project has aimed to improve spatial resolution of Raman and luminescence spectroscopy. A variety of samples such as carbon nanotubes, gold-metal nano triangles, molecular aggregates were adsorbed at the surfaces of graphite or indium tin oxide plates. The instruments for these measurements were designed and built up in the laboratory. Tunneling probes were made with the electro-chemical etching of silver/copper metal alloy wires or chemical coating of silver metal on electro-chemically sharpened tungsten wires. We have found that the spatial resolution of Raman spectroscopy was improved to be in the range of several tens of nanometer when nanotubes were measured ; however, the topographical images did not always correspond with the spectral images. This deviation is considered to be due to differences in the spaces where the plasmonic enhancement takes place and the tunneling current flows. Photoluminescence of cadmium serenade quantum dots on indium tin oxide plates showed significant dependence on the distance between the quantum dots and tunneling probes with a nanometer precision. Gold nano triangles adsorbed on indium tin oxide surfaces were found to give good atomic-flat surfaces for scanning tunneling microscopy as well as to give semi-transparent substrates for inverse-type optical microscopy. Moreover, we found that some parts of gold nano triangles emitted luminescence only by approaching tunneling probes. These results are expected to contribute the development of high spatial resolution spectroscopy for the nano world.