压膜阻尼对原子力显微镜振动特性的影响研究

Study on the influence of squeeze-film damping on the vibration characteristics of atomic force microscopy

原子力显微镜(Atomic Force Microscope,AFM)在轻敲模式下工作时,随着探针针尖与样品距离的逐渐减小,空气压膜阻尼的作用随之增大。为研究压膜阻尼对原子力显微镜振动系统的影响,分别使用无针尖探针和微球针尖探针进行扫频实验,并基于振动理论将该过程简化,得到了两种不同的振动模型的系统刚度。在考虑压膜阻尼作用影响后,将微球针尖振动系统模型进一步简化为一维振子模型,并对压膜阻尼的影响进行讨论。实验表明空气压膜阻尼模型对于探针样品在微尺度下的作用过程是准确合理的。该结果对原子力显微镜轻敲模式研究具有重要意义。

In Atomic Force Microscope(AFM)tapping mode,as the distance between the tip and the sample decreases,the effect of squeeze filmair damping increases gradually.In order to explore the influence of squeeze film damping on the vibration system of AFM,the tune experiments were carried out using the tipless probe and the microsphere tip probe.The process was simplified based on the vibration theory,in which the system stiffness of two different vibration models was obtained.Considering the influence of the squeeze film damping,the sphere tip vibration system model was further simplified to a one-dimensional oscillator model,and the influence of the squeeze film damping was discussed.The results show that the squeeze film damping model is accurate and reasonable for the action of probes and samples at micro-scale.The result is of great significance to the AFM tapping mode study.