Abstract
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.
Highlights
Dynamic atomic force microscopy (AFM) was introduced in the late 1980s [1] as the natural evolution of the first atomic force microscopes [2]
One should note that if we talk of the interaction stiffness, ki, this contains the implicit assumption that the interaction force, Fi, in the vicinity of the tip oscillation can be expressed approximately as Fi = F0 − kix, with F0 being a constant and x being the tip position
We have introduced a methodology to directly derive the conservative and dissipative interactions between the AFM probe and the sample in dynamic AFM experiments when small oscillation amplitudes of the tip are used, and for different tip excitation and detection schemes
Summary
Dynamic atomic force microscopy (AFM) was introduced in the late 1980s [1] as the natural evolution of the first atomic force microscopes [2]. If the tip position is not measured and the cantilever is not directly excited, Equation 6 does not hold, away from the resonance frequency or when the Q factor is small.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
