Hao Lifeng, Wang Qi, Peng Ping, Cao Zhenxing, Jiao Weicheng, Yang Fan, Liu Wenbo, Wang Rongguo, He Xiaodong
Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150080, China.
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Ultramicroscopy. 2017 Mar;174:106-111. doi: 10.1016/j.ultramic.2016.12.015. Epub 2016 Dec 23.
Determining sensor parameters is a prerequisite for quantitative force measurement. Here we report a direct, high-precision calibration method for quartz tuning fork (TF) sensors that are popular in the field of nanomechanical measurement. In the method, conservative and dissipative forces with controlled amplitudes are applied to one prong of TF directly to mimic the tip-sample interaction, and the responses of the sensor are measured at the same time to extract sensor parameters. The method, for the first time, allows force gradient and damping coefficient which correspond to the conservative and dissipative interactions to be measured simultaneously. The calibration result shows surprisingly that, unlike cantilevers, the frequency shift for TFs depends on both the conservative and dissipative forces, which may be ascribed to the complex dynamics. The effectiveness of the method is testified by force spectrum measurement with a calibrated TF. The method is generic for all kinds of sensors used for non-contact atomic force microscopy (NC-AFM) and is an important improvement for quantitative nanomechanical measurement.
确定传感器参数是进行定量力测量的前提条件。在此，我们报道了一种针对石英音叉（TF）传感器的直接、高精度校准方法，该传感器在纳米力学测量领域颇受欢迎。在该方法中，将具有可控振幅的保守力和耗散力直接施加到TF的一个叉臂上，以模拟针尖与样品之间的相互作用，同时测量传感器的响应以提取传感器参数。该方法首次实现了与保守相互作用和耗散相互作用相对应的力梯度和阻尼系数的同时测量。校准结果令人惊讶地表明，与悬臂梁不同，TF的频率偏移取决于保守力和耗散力两者，这可能归因于其复杂的动力学特性。通过使用校准后的TF进行力谱测量，验证了该方法的有效性。该方法适用于所有用于非接触原子力显微镜（NC-AFM）的传感器，是对定量纳米力学测量的一项重要改进。
