Tapping atomic force microscopy imaging at phase resonance

Tapping atomic force microscope (TM-AFM) can measure soft samples, which has the advantages of low loss and high resolution, and has been widely used in the characterization of soft micro-nano materials by atomic force microscope (AFM). The phase image in TM-AFM contains sample properties, and it is an important method to characterize the sample by TM-AFM. At present, researchers usually select the frequency near the first resonance peak of the probe to drive its vibration to carry out scanning imaging. However, the phase sensitivity near the first-order resonance of the probe is not high. Therefore, the phase image of TM-AFM is also less sensitive to characterize micro-nano materials. In order to improve the phase sensitivity of the probe, the probe working at the phase resonance peak was selected in this paper to improve the phase sensitivity of the probe vibration and the imaging quality of TM-AFM phase image. The experimental results show that the phase image of phase resonance-atomic force microscope (PR-AFM) can provide not only the surface information but also the structure information of the sample subsurface. PR-AFM can be applied for better characterization of micro and nano materials.