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原子力显微镜(atomic force microscope,AFM)作为微纳米研究中的重要工具,被广泛地应用于微纳米尺度上样品表面高度的测量.但是,AFM扫描时针尖对样品存在下压效应,即扫描得到的样品表面高度由于针尖施加的压力而小于其真实值.而至今为止,还没有一种快速、有效的补偿下压效应所带来的高度测量误差的方法.本文通过对AFM工作原理及其下压效应机理的详细分析,充分利用AFM偏转测量和高度测量的信息冗余性及互补性,提出了一种利用数据融合和参数辨识来自动补偿AFM下压效应的方法。首先,通过力曲线概念分析了下压效应的产生机理;然后,从力曲线出发,提出一种基于信息融合和参数辨识的AFM下压效应的补偿方法.值得指出的是,由于力曲线斜率是样品表面弹性特征的一种有效表示方式,本文算法在提高AFM高度测量精度的同时,还能够自动(在线)地获取样品的表面弹性特征,从而进一步扩展了AFM的应用。最后,通过扫描滴在硅基底上的多壁碳纳米管以及云母基底上的石墨烯进行了试验研究,以验证该方法的正确性和有效性。
Atomic force microscope (AFM), as an important tool in micro-nano research, is widely used to measure the surface height of a sample in the micro-nano scale, however, the AFM tip has a downward pressure on the sample, ie, the scanned The sample surface height is less than its true value due to the pressure exerted by the needle tip, but so far there is no fast and effective method of compensating the height measurement error caused by the pressure effect.Based on the working principle of AFM and its pressure In order to make full use of the information redundancy and complementarity of AFM deflection measurement and altitude measurement, a method of automatically compensating the AFM depression effect using data fusion and parameter identification is proposed. Firstly, the generation mechanism of the depression effect is analyzed by the concept of force curve. Then, based on the force curve, a compensation method of the AFM depression effect based on information fusion and parameter identification is proposed. It is worth noting that since the slope of the force curve is An effective representation of the surface elastic characteristics of the sample, the proposed algorithm can automatically (on-line) obtain the surface elastic characteristics of the sample while improving the accuracy of the AFM measurement, thus further extending the application of the AFM. Finally, the multi-walled carbon nanotubes deposited on the silicon substrate and the graphene on the mica substrate were scanned to verify the correctness and effectiveness of the method.