激励频率对TM-AFM相位成像的影响

魏瑞华,彭安杰 ,宾凤姣 ,魏 征*

激励频率对TM-AFM相位成像的影响

魏瑞华,彭安杰 ,宾凤姣 ,魏  征*

(北京化工大学 机电工程学院,北京,100029)

    相位成像是轻敲模式下原子力显微镜(tapping mode atomic force microscope,TM-AFM)最具有特色的成像方式。本文以获得高质量的相位像为主要研究目的,利用Euler-Bernoulli(欧拉-伯努利)梁方程,将系统动力学模型简化为基于支承运动的弹簧谐振子模型,推导出相位与激励频率之间的关系。实验结果与理论分析一致,这一结论对于寻找TM-AFM操作中最合适的激励频率范围具有重要意义。

关键词   原子力显微镜;轻敲模式;激励频率;相位成像;相位对比度   

中图分类号:O657;Q6-3;TH742 

文献标识码:Adoi:10.3969/j.issn.1000-6281.2021.06.005

 

Effect of excitation frequency on TM-AFM phase imaging

WEI Rui-hua,PENG An-jie,Bin Feng-jiao,WEI Zheng*

(School of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029,China)

Abstract   Phase imaging is the most characteristic imaging mode of the TM-AFM. The main purpose of this paper is to obtain high quality phase images. The Euler-Bernoulli beam equation was used to solve the vibration equation by analyzing the dynamic model of TM-AFM micro-cantilever beam. According to the vibration content, the dynamic model was simplified to the spring harmonic oscillator model based on the bearing motion and the relation between the phase and the excitation frequency was deduced. Experiments were designed according to the relation between phase and frequency obtained from the derivation. The excitation frequency was changed to make it close to the first-order natural frequency until it reached the first-order natural frequency. The results of the experiments are consistent with the theoretical analysis, which is of great significance for finding the most suitable excitation frequency range in TM-AFM operation.

Keywords   AFM; tapping mode; exciting frequency; phase imaging; phase contrast

 

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