Optimizing atomic resolution of force microscopy in ambient conditions
Optimizing atomic resolution of force microscopy in ambient conditions
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DOI：
10.1103/physrevb.87.245415
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发表时间：
2013-06-12
影响因子：
3.7
通讯作者：
Giessibl, Franz J.
中科院分区：
文献类型：
--
作者：
Wastl, Daniel S.;Weymouth, Alfred J.;Giessibl, Franz J.
环境操作对原子力显微镜提出了挑战，因为与真空或液体环境中的操作相比，悬臂动力学在探测样品时从空气中的振荡转变为水化层中的振荡。我们用基于石英音叉的悬臂(qPlus传感器)的频率调制原子力显微镜，在环境条件下通过对KBr(001)表面的成像来演示原子分辨率，并分析了对衰减的长程和短程贡献。水化层厚度随相对湿度的增加而增加，因此，改变湿度可以研究水化层厚度对悬臂梁阻尼的影响。我们从测量衰减与幅度的关系入手，分析了原子尺度上的信号和噪声特性。然后，我们确定了使我们能够获得高质量原子分辨率图像的最佳幅度。
Ambient operation poses a challenge to atomic force microscopy because in contrast to operation in vacuum or liquid environments, the cantilever dynamics change dramatically from oscillating in air to oscillating in a hydration layer when probing the sample. We demonstrate atomic resolution by imaging of the KBr(001) surface in ambient conditions by frequency-modulation atomic force microscopy with a cantilever based on a quartz tuning fork (qPlus sensor) and analyze both long- and short-range contributions to the damping. The thickness of the hydration layer increases with relative humidity; thus varying humidity enables us to study the influence of the hydration layer thickness on cantilever damping. Starting with measurements of damping versus amplitude, we analyzed the signal and the noise characteristics at the atomic scale. We then determined the optimal amplitude which enabled us to acquire high-quality atomically resolved images.