Ruppert Michael G, Routley Ben S, McCourt Luke R, Yong Yuen K, Fleming Andrew J
University of Technology Sydney, Centre for Audio, Acoustics and Vibration, Ultimo, NSW 2007, Australia.
The University of Newcastle, Callaghan, NSW 2308, Australia.
Nano Lett. 2025 Apr 9;25(14):5656-5662. doi: 10.1021/acs.nanolett.4c06397. Epub 2025 Mar 13.
This article presents a proof-of-concept for a new imaging method that combines tip-enhanced Raman spectroscopy with intermittent-contact atomic force microscopy to provide simultaneous nanometer-scale mechanical imaging with chemical contrast. The foremost difference from a standard tip-enhanced Raman microscope is the Raman illumination, which is modulated by the cantilever drive signal so that illumination is only active when the tip is close to the surface. This approach significantly reduces contact forces and thermal damage due to constant illumination while simultaneously reducing background Raman signals. Near-field optical and dynamic cantilever simulations highlight the effect of the imaging parameters on the tip-sample force and the evanescent field enhancement. The experimental images obtained with this new imaging method demonstrate a lateral resolution sufficient to identify single-walled carbon nanotube bundles with a full width at half-maximum of 20 nm.
本文介绍了一种新成像方法的概念验证，该方法将尖端增强拉曼光谱与间歇接触原子力显微镜相结合，以提供具有化学对比度的同时纳米级机械成像。与标准尖端增强拉曼显微镜最主要的区别在于拉曼照明，它由悬臂驱动信号调制，使得仅当尖端靠近表面时照明才有效。这种方法显著降低了由于持续照明导致的接触力和热损伤，同时减少了背景拉曼信号。近场光学和动态悬臂模拟突出了成像参数对尖端-样品力和倏逝场增强的影响。用这种新成像方法获得的实验图像显示出足够的横向分辨率，能够识别半高宽为20纳米的单壁碳纳米管束。
