Finite sample thickness effects on elasticity determination using atomic force microscopy
Finite sample thickness effects on elasticity determination using atomic force microscopy
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DOI：
10.1021/la980585z
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发表时间：
1999-08-17
期刊：
影响因子：
3.9
通讯作者：
Walker, GC
中科院分区：
文献类型：
--
作者：
Akhremitchev, BB;Walker, GC
计算了有限样品厚度对原子力显微镜测量材料弹性的影响。该模型包括弹性地基上的弹性层，模拟了在外加载荷作用下试件的压痕。考虑了具有圆锥形、抛物面和双曲面的刚性轴对称叶尖。结果表明，根据力-位移曲线估算弹性模量的常用方法可能会导致与测量单位有关的显著误差。提出了一种明确估计和修正这一误差的方法。此外，研究还表明，使用力调制技术对单层厚样本的弹性估计可能包含相当大的样本厚度相关误差。对于几纳米厚的样品，局部厚度变化可能会在力调制图像中产生误导的对比度。
Finite sample thickness effects on material elasticity measurements made using an atomic force microscope have been calculated. The model includes an elastic layer on an elastic foundation and simulates sample indentation under an applied load. Rigid axisymmetric tips with conical, paraboloidal, and hyperboloidal profiles are considered. The results show that a common approach to estimating elastic moduli from force-displacement curves can lead to a significant error that depends on the units of measurement. A method to unambiguously estimate and correct this error is proposed. In addition, it is shown that elasticity estimates for monolayer thick samples using the force-modulation technique can contain a substantial, sample thickness-dependent error. Local thickness variations can result in misleading contrast in force-modulation images for samples that are several nanometers thick.