非共振轻敲模式原子力显微镜的研究

Research on non-resonant tapping mode atomic force microscope

原子力显微镜(AFM)是在微纳尺度观测以及操纵样品的重要工具。与传统的接触模式和轻敲模式AFM相比,非共振轻敲模式AFM因为其控制力精度高并可同步获取多种机械特性等优势得到了广泛的应用。采用基于背景相减和同步算法相结合的方法搭建了一套自制的非共振轻敲模式AFM,并对位置检测电路建立了通用噪声仿真模型,优化了位置检测电路噪声,从而优化了最小可控力的精度,使其最小可控力小于50 pN。接着通过对标准硅材料栅格进行形貌表征验证了系统的成像性能,以及对复合材料的形貌、粘附力、形变等多种力学性质表征,验证了系统及成像方法的有效性。

Atomic force microscopy(AFM) is an important tool for observing and manipulating samples at micro-nanometer scale. Compared with traditional contacting mode and tapping mode AFMs, the non-resonant tapping mode AFM has got wide applications due to its high accuracy control force and the ability to acquire multiple mechanical characteristics simultaneously. In this paper, adopting the method based on combining the background subtraction and synchronization algorithm, a home-built non-resonant tapping mode AFM is built. A general noise simulation model is established for the position detection circuit, the position detection circuit noise is optimized, so that the precision of the minimum controllable force is improved, which makes the minimum controllable force smaller than 50 pN. The morphology characterization of the standard silicon lattice was performed to verify the imaging performance of the system. And the characterization of various mechanical properties of composite materials, such as morphology, adhesion force and deformation was carried out to verify the effectiveness of the system and the imaging method.