Combining TEM, AFM, and Profilometry for Quantitative Topography Characterization Across All Scales
Combining TEM, AFM, and Profilometry for Quantitative Topography Characterization Across All Scales
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DOI：
10.1021/acsami.8b09899
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发表时间：
2018-08-29
影响因子：
9.5
通讯作者：
Jacobs, Tevis D. B.
中科院分区：
文献类型：
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作者：
Gujrati, Abhijeet;Khanal, Subarna R.;Jacobs, Tevis D. B.
表面粗糙度影响表面的功能特性，包括附着力、摩擦力、疏水性、生物响应以及电和热传输特性。然而，量化这些联系的实验研究往往是不确定的，因为表面是类分形的，并且测量的粗糙度参数的值取决于测量尺寸。在这里，我们展示了超纳米晶金刚石(UNCD)表面在埃尺度上的形貌表征，以及它与传统技术的结合，以实现跨越8个数量级的全面表面描述。我们使用透射电子显微镜和传统技术(触针轮廓术和原子力显微镜)对纳米金刚石薄膜进行了100多次单独测量。虽然均方根(RMS)高度、均方根斜率和均方根曲率的单独测量结果会有几个数量级的变化，但我们结合了使用功率谱密度的各种技术，并使用它来计算与尺度无关的参数。这一分析表明，“光滑的”UNCD表面的均方根斜率大于1，甚至比奥地利阿尔卑斯山的斜率还要大，如果以人的步数来衡量的话。这种综合的多尺度粗糙度表征方法，以埃尺度细节测量，将使其他技术相关表面的系统评估和优化，以及对许多粗糙表面行为的分析和数值模型的系统测试成为可能。
Surface roughness affects the functional properties of surfaces, including adhesion, friction, hydrophobicity, biological response, and electrical and thermal transport properties. However, experimental investigations to quantify these links are often inconclusive because surfaces are fractal-like, and the values of measured roughness parameters depend on measurement size. Here, we demonstrate the characterization of topography of an ultrananocrystalline diamond (UNCD) surface at the angstrom scale using transmission electron microscopy (TEM), as well as its combination with conventional techniques to achieve a comprehensive surface description spanning 8 orders of magnitude in size. We performed more than 100 individual measurements of the nanodiamond film using both TEM and conventional techniques (stylus profilometry and atomic force microscopy). While individual measurements of root-mean-square (RMS) height, RMS slope, and RMS curvature vary by orders of magnitude, we combine the various techniques using the power spectral density and use this to compute scale-independent parameters. This analysis reveals that "smooth" UNCD surfaces have an RMS slope greater than 1, even larger than the slope of the Austrian Alps when measured on the scale of a human step. This approach of comprehensive multiscale roughness characterization, measured with angstrom-scale detail, will enable the systematic evaluation and optimization of other technologically relevant surfaces, as well as systematic testing of the many analytical and numerical models for the behavior of rough surfaces.