Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.
Nanotechnology. 2010 Feb 10;21(6):065710. doi: 10.1088/0957-4484/21/6/065710. Epub 2010 Jan 8.
In this work, we demonstrate that high-resolution imaging in water with a soft contact between the tip and the sample can be achieved with frequency-modulation torsional resonance (FM-TR) mode atomic force microscopy (AFM). This mode is very sensitive to the contact of the tip with the sample surface. A sharp jump in the resonance frequency shift occurs when the tip is getting in touch with the sample. Individual atomic features on mica surfaces can be resolved with a relatively large tip. The tip applies very small normal and lateral forces on the surface. In addition, even a long and compliant AFM cantilever can achieve a high quality factor and a high resonant frequency for the torsional oscillation in water. Along with several other advantages, this mode is very suitable for future development of high-sensitivity, high-resolution, high-speed AFM for the study of dynamic biological processes in liquid.
在这项工作中，我们证明了在针尖与样品之间具有软接触的情况下，可以通过调频扭转共振（FM-TR）模式原子力显微镜（AFM）实现水中的高分辨率成像。这种模式对针尖与样品表面的接触非常敏感。当针尖与样品接触时，共振频率的偏移会出现明显的跳跃。云母表面的单个原子特征可以用相对较大的针尖来分辨。针尖对表面施加的法向和侧向力非常小。此外，即使是长而柔顺的 AFM 悬臂梁，也可以在水中实现高的扭转振动品质因数和高的共振频率。除了其他几个优点外，这种模式非常适合未来发展用于研究液体中动态生物过程的高灵敏度、高分辨率、高速 AFM。
