Costa Luca, Rodrigues Mario S
ESRF, The European Synchrotron, 71 Rue des Martyrs, 38000 Grenoble, France.
CFMC/Dep. de Física, Universidade de Lisboa, Campo Grande 1749-016 Lisboa, Portugal.
Beilstein J Nanotechnol. 2015 Feb 10;6:420-7. doi: 10.3762/bjnano.6.42. eCollection 2015.
The quantification of the tip-sample interaction in amplitude modulation atomic force microscopy is challenging, especially when measuring in liquid media. Here, we derive formulas for the tip-sample interactions and investigate the effect of spurious resonances on the measured interaction. Highlighting the differences between measuring directly the tip position or the cantilever deflection, and considering both direct and acoustic excitation, we show that the cantilever behavior is insensitive to spurious resonances as long as the measured signal corresponds to the tip position, or if the excitation force is correctly considered. Since the effective excitation force may depend on the presence of such spurious resonances, only the case in which the frequency is kept constant during the measurement is considered. Finally, we show the advantages that result from the use of a calibration method based on the acquisition of approach-retract curves.
在幅度调制原子力显微镜中，对针尖 - 样品相互作用进行量化具有挑战性，尤其是在液体介质中进行测量时。在此，我们推导了针尖 - 样品相互作用的公式，并研究了杂散共振对测量到的相互作用的影响。突出直接测量针尖位置或悬臂梁偏转之间的差异，并考虑直接激励和声激励，我们表明，只要测量信号对应于针尖位置，或者如果正确考虑激励力，悬臂梁的行为对杂散共振不敏感。由于有效激励力可能取决于此类杂散共振的存在，因此仅考虑测量期间频率保持恒定的情况。最后，我们展示了使用基于获取接近 - 退回曲线的校准方法所带来的优势。
