González Martínez Juan Francisco, Nieto-Carvajal Inés, Abad José, Colchero Jaime
Instituto Universitario de Investigación en Óptica y Nanofísica, Campus de Espinardo, Universidad de Murcia, E-30100 Murcia, Spain.
Nanoscale Res Lett. 2012 Mar 7;7(1):174. doi: 10.1186/1556-276X-7-174.
In this study, we show that the correct determination of surface morphology using scanning force microscopy (SFM) imaging and power spectral density (PSD) analysis of the surface roughness is an extremely demanding task that is easily affected by experimental parameters such as scan speed and feedback parameters. We present examples were the measured topography data is significantly influenced by the feedback response of the SFM system and the PSD curves calculated from this experimental data do not correspond to that of the true topography. Instead, either features are "lost" due to low pass filtering or features are "created" due to oscillation of the feedback loop. In order to overcome these serious problems we show that the interaction signal (error signal) can be used not only to quantitatively control but also to significantly improve the quality of the topography raw data used for the PSD analysis. In particular, the calibrated error signal image can be used in combination with the topography image in order to obtain a correct representation of surface morphology ("true" topographic image). From this "true" topographic image a faithful determination of the PSD of surface morphology is possible. The corresponding PSD curve is not affected by the fine-tuning of feedback parameters, and allows for much faster image acquisition speeds without loss of information in the PSD curve.
在本研究中，我们表明，使用扫描力显微镜（SFM）成像和表面粗糙度的功率谱密度（PSD）分析来正确确定表面形态是一项极具挑战性的任务，很容易受到诸如扫描速度和反馈参数等实验参数的影响。我们给出了一些示例，其中测量的形貌数据受到SFM系统反馈响应的显著影响，并且根据该实验数据计算出的PSD曲线与真实形貌的PSD曲线不相符。相反，由于低通滤波，特征会“丢失”，或者由于反馈回路的振荡，特征会“被创建”。为了克服这些严重问题，我们表明，相互作用信号（误差信号）不仅可以用于定量控制，还可以显著提高用于PSD分析的形貌原始数据的质量。特别是，经过校准的误差信号图像可以与形貌图像结合使用，以获得表面形态的正确表示（“真实”形貌图像）。从这个“真实”形貌图像中，可以准确地确定表面形态的PSD。相应的PSD曲线不受反馈参数微调的影响，并且允许更快的图像采集速度，而不会在PSD曲线中丢失信息。
