Investigation of the carbon nanotube AFM tip contacts: free sliding versus pinned contact

Abstract

Mechanical response of carbon nanotube atomic force microscope probes are investigated using a thermal noise forcing. Thermal noise spectra are able to investigate mechanical behaviors that cannot be studied using classical atomic force microscope modes. Experimental results show that the carbon nanotube contacts can be classified in two categories: the free sliding and pinned cases. The pinned contact case requires the description of the cantilever flexural vibrations with support spring-coupled cantilever boundary conditions. Our experimental results show that carbon nanotubes exhibit different contact behaviors with a surface, and in turn different mechanical responses.

Longitudinal Vibration of CNTs Viscously Damped in Span

“…[11] Khademolhosseini, F., Phani, A.S., Nojeh, A., Rajapakse, N., Nonlocal continuum modeling and molecular dynamics simulation of torsional vibration of carbon nanotubes, IEEE Transactions on Nanotechnology, 11, [34][35][36][37][38][39][40][41][42][43]2012 …”

Dynamic stiffness of the contact between a carbon nanotube and a flat substrate in a peeling geometry

“…We can thus easily compute the contact stiffness k c from the angular frequency ω c of the resonance 13,14,25 : and from thermal noise analysis (fc). The dynamic stiffness is higher than the quasi-static one, and is almost constant on the force plateau.…”

“…The resonance frequency is measured from the noise spectrum of the cantilever 13,14,25 : the power spectrum density (PSD) of the fluctuations of deflection, induced by the thermal noise random forcing, is sharply peaked at ω c , as illustrated in figure 2(c). During the quasi-static ramp, we compute the PSD on a 0.4 s sliding time window, thus corresponding to only a 4 nm vertical translation of the sample.…”

Carbon Nanotube AFM Probe Technology

“…Generally, thermal noise forcing produces probe oscillation amplitudes only about angstrom. Therefore, the thermal noise spectrum is very sensitive to tiny variations of the contact properties between the CNT probe and the surface, thus providing an accurate picture of the CNT probe's mechanical response (Buchoux et al, 2009). Molecular simulations were proposed to explain the effects of CNT's slip and snap-to-contact on the resolutions (Solares & Chawla, 2010).…”