Identification of multiple oscillation states of carbon nanotube tipped cantilevers interacting with surfaces in dynamic atomic force microscopy

Abstract

Carbon nanotubes ͑CNTs͒ have gained increased interest in dynamic atomic force microscopy ͑dAFM͒ as sharp, flexible, conducting, nonreactive tips for high-resolution imaging, oxidation lithography, and electrostatic force microscopy. By means of theory and experiments we lay out a map of several distinct tapping mode AFM oscillation states for CNT tipped AFM cantilevers: namely, noncontact attractive regime oscillation, intermittent contact with CNT slipping or pinning, or permanent contact with the CNT in point or line contact with the surface while the cantilever oscillates with large amplitude. Each state represents fundamentally different origins of CNT-surface interactions, CNT tip-substrate dissipation, and phase contrast and has major implications for the use of these probes for imaging, compositional contrast, and lithography. In particular, we present a method that uses energy-dissipation spectroscopy to identify if the CNT slips laterally on the surface or remains pinned in the intermittent contact regime. By comparing phase contrast images and energy dissipation on graphite, graphene oxide, and silicon oxide surfaces, we demonstrate the utility of the method in identifying pinning or slipping of the CNT on the surface in the intermittent contact regime.

Atomic force microscope measurements andLCAO−S2 + vdW calculations of contact length between a carbon nanotube and a graphene surface

“…In the case of a single CNT, one part lies parallel to the surface whereas the other remains almost vertically attached to the tip, and the curvature radius depends on the applied load and on the tube diameter. [35][36][37] Here, the CNT-surface interaction is mainly piloted by van der Waals (vdW) interactions. One can find a natural extension by considering an important number of grafted CNT's on a substrate, leading to vertical CNT arrays.…”

“…50 They also indentified how the CNT may interact by pinning or slipping with the surface during the intermittent contact regime of the AFM. 37 González et al presented a combined experimental and theoretical study of the interaction between a tip and SWCNT's lying on a SiO 2 surface. Adhesion and jump-to-contact forces (JC) are measured in a high vacuum system for SWCNT's with diameters ranging from 1.4 to 4.5 nm.…”

Carbon Nanotube AFM Probe Technology

“…The pinning or slipping of the CNT depends on the scan surface and the CNT probe's stiffness. It is found that CNT probe is easier slipping on the graphite surface than on the graphene oxide and silicon oxide surfaces (Strus & Raman, 2009). The CNT probe's slipping effect was experimental studied .…”

“…When CNT probes are operated in the net repulsive regime, CNTs have the potential to buckle, bend, adhere, and slide (Strus & Raman, 2009). Many studies highlighted that the CNT probe-sample boundary conditions and its mechanical responses would play a vital role in the CNT probe's stability.…”

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

“…For example, the AFM has been successfully used to characterize the adhesion of one dimensional nano-object, such as carbon nanotubes [3][4][5][6] . In particular, in peeling experiments, one measures the force while the nanotube is pulled from a flat substrate [7][8][9][10][11][12][13][14] . The force versus distance curve displays a signature specific to this peeling process, and can be used to extract the energy of adhesion between the nano-object and the surface.…”