原子力显微镜法测试石墨烯厚度的数据处理方法对比

Comparison of data processing methods for testing graphene thickness using atomic force microscopy

原子力显微镜可用于石墨烯厚度的测定。列举三种常用的原子力显微镜厚度数据处理方法:平均值法、最小二乘法和直方图法。从石墨烯原子力显微镜测试图像中选取216组横向截面高度数据,从原理、结果分析、优缺点等方面对三种数据处理方法进行对比和探讨。结果表明:三种数据处理方法所得厚度结果的相关性极强;平均值法和最小二乘法的厚度计算在数学上是等价的,计算过程均不受数据量影响,最小二乘法拟合的斜率可反映台阶倾斜情况;直方图法可以有效减少吸附污染物和噪声效应对厚度计算的影响,数据量过少不利于高斯拟合,且数据量越大高斯拟合越精准,在数据量较多的情况下宜采用直方图法。

The atomic force microscope can be used to measure the thickness of graphene.Three commonly used methods for processing atomic force microscopy thickness data are described:the mean value method,least squares method,and histogram method.216 sets of transverse section height data were selected from the test images of graphene and the three data processing methods were compared and discussed in terms of principles,results analysis,advantages,and disadvantages.The results show that the correlation between the thickness results obtained by the three data processing methods is extremely strong.The thickness calculations of the mean value method and the least squares method are mathematically equivalent,and the calculation process is not affected by the amount of data.The slope fitted by the least squares method can reflect the inclination of steps;the histogram method can effectively reduce the influence of adsorbed pollutants and noise on thickness calculation.A small amount of data is not conducive to Gaussian fitting,and the larger the amount of data,the more accurate the Gaussian fitting will be.Hence,the histogram method is suitab le for use when dealing with large amounts of data.