| Author Name | Affiliation | | Hongyu Ju | School of Life Science and Engineering, Key Lab of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China | | Song Zhang | School of Life Science and Engineering, Key Lab of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China | | Shuxun Cui | School of Life Science and Engineering, Key Lab of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China |
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| Abstract: |
| Thermal vibration of the cantilevers is the main source of noise in atomic force microscopy (AFM). When immersed in liquids, the dynamic behavior of the cantilevers will be significantly affected by the environment. In this study, the effects of environments on the noise of AFM were investigated. The results show that the V-shaped cantilever exhibited very low noise in high vacuum. The noise in atmospheric environment was also satisfactory. In liquid environments, the noise dramatically increased. The systematic noise was low and dependent on the distance between the tip and substrate. As the velocity increased, the noise of V-shaped cantilever was increased in a similar trend. It is also found that the variation trend was more pronounced as the liquid viscosity increased. The noise of rectangular cantilever was lower than that of V-shaped cantilever in the same environment. The present study indicates that high vacuum is an ideal environment for single molecule force spectroscopy (SMFS) due to the lower noise and higher resolution. For a better signal-to-noise ratio, both the cantilever velocity and liquid viscosity should be as low as possible. These results will be helpful when a lower noise is desired in weak force detection. |
| Key words: atomic force microscopy cantilever noise high vacuum viscosity |
| DOI：10.11916/j.issn.1005-9113.2020007 |
| Clc Number:TH73 |
| Fund: |
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| Descriptions in Chinese: |
| 环境对原子力显微镜悬臂噪声的影响 句宏宇 张松 崔树勋 （西南交通大学 生命科学与工程学院 材料先进技术教育部重点实验室，四川 成都 610031） 创新点说明：1）发现了原子力显微镜（AFM）在高真空环境中具有非常小的噪声； 2）发现了AFM在液体环境中的噪声与液体粘度和悬臂运动速率之间的关系。 研究目的： 得到AFM的噪声和使用环境、悬臂种类以及仪器参数设置之间的关系，找出减小AFM噪声的有效方法。 研究方法： 模拟基于AFM的单分子力谱实验过程，通过计算AFM在高真空、大气和不同粘度液体环境中不同运动速率下力信号数值的标准差（即噪声大小），分析AFM噪声的影响因素。 研究结果： 1）V形悬臂在高真空环境中具有非常小的噪声，在大气环境中噪声有微小增大，在液体环境中噪声显著增大； 2）AFM具有较低的系统噪声，且系统噪声大小和悬臂到基底的距离相关； 3）随着悬臂运动速率的增加，V形悬臂在不同粘度液体环境中的噪声表现出相似的增大趋势。且液体黏度越大，噪声随速率增大的趋势越显著； 4）相同环境中矩形悬臂的噪声小于V形悬臂的噪声。 结论： 1）高真空环境中AFM具有较小的噪声和较高的分辨率，是进行单分子力谱实验的理想环境； 2） 在液体环境中为了获得较高的信噪比，应尽可能地减小悬臂的运动速率和液体粘度。 关键词：原子力显微镜；悬臂；噪声；高真空；粘度 |
