High Resolution Near-Field Raman Spectroscopy of Carbon Nanotubes

罗切斯特大学的卢卡斯·诺沃特尼教授得到了碳纳米管近场拉曼光谱分析和表面化学项目的支持。这个想法是将近场尖端靠近碳纳米管的表面，然后用激光照射尖端。增强的拉曼信号在纳米管上产生该局部的振动光谱，分辨率为10纳米。沿着样品平移尖端允许PI沿着管子的长度映射局部振动特征，并研究管子末端和管子上的接头。PI也在研究拉曼增强的机理。以前，碳纳米管很难用光谱学研究，因为宏观样品是不均匀的，包括许多长度。通过一次研究一根管子，PI和他的团队能够获得孤立的光谱，这些光谱揭示了如果管子中加载了另一种元素，如缺陷和掺杂剂等特征。PI与同样来自罗切斯特大学的托德·克劳斯合作制作样品。了解掺杂剂在碳纳米管吸收氢中的作用与燃料电池技术有关。此外，对碳纳米管物理性质的有价值的反馈将导致新的器件概念，并为改进合成提供输入。虽然这项工作特别适合于纳米管，但该方法的发展也将有助于对其他微小结构进行化学成像，例如可能在活细胞内发现的那些结构。样品的化学成像是理解生物和材料系统中结构和功能关系的重要目标。

Professor Lukas Novotny of University of Rochester is supported by the Analytical and Surface Chemistry program for near-field Raman spectroscopy of carbon nanotubes. The idea is to bring a near field tip close to the surface of a carbon nanotube and then to irradiate the tip with a laser. Enhanced Raman signals yield the vibrational spectrum of that locality on the nanotube with 10 nanometer resolution. Translating the tip along the sample allows the PI to map the local vibrational character along the tube's length and to study the tube ends and on-tube junctions. The PI is also studying the mechanism of the Raman enhancement. Previously, carbon nanotubes have been difficult to study spectroscopically because a macroscopic sample is heterogeneous, encompassing many lengths. By studying one tube at a time, the PI and his group are able to get the isolated spectra that reveal features such as defects and dopants if the tube is loaded with another element such as boron. The PI collaborates with Todd Krauss, also of U. Rochester, to fabricate the samples. Understanding the role of dopants in the uptake of hydrogen by carbon nanotubes is relevant to fuel cell technologies. Further, the valuable feedback on the physical properties of carbon nanotubes will lead to new device concepts, and provide input for improved synthesis. While the work is particularly well suited to nanotubes, the development of the method will also benefit efforts to chemically image other small structures such as those that might be found inside a living cell. Chemical imaging of samples is an important goal for understanding the relationship of structure and function in biological and material systems.