Atomic force microscopy and spectroscopy

Abstract

Since it was invented by Binnig et al in 1986, atomic force microscopy (AFM) has played a crucial role in nano-scale science and technology. AFM is a microscopic technique imaging a surface topography by using attractive and repulsive interaction forces between a few atoms attached at a tip on a cantilever and a sample. In the case of attractive forces, there are three main contributions causing AFM. These are short-range chemical force, van der Waals force and electrostatic force. As the effective ranges of these forces are different, one of them is dominant depending on distance. Atomic force spectroscopy is the force-versus-distance measurement when using AFM. The atomic force can be detected by cantilever bending caused by a tip-sample interacting force, which is called static AFM. Also, the atomic force can be detected by using the resonant properties of a cantilever, which is called dynamic AFM. Under the on-resonance condition, the frequency, amplitude or phase of the cantilever will be shifted by the interaction force. While the force can be estimated in static AFM, for dynamic AFM it requires complicated formalism to evaluate the force from measured amplitude, phase or frequency data. Recently developed techniques for ultra-high resolution imaging unveil sub-atomic features of the sample, which are facilitated by low temperature, ultra-high vacuum environments together with a stiff cantilever. In this study, progress related to theoretical and experimental imaging and force spectroscopy will be discussed.

Sintering process of amorphous SiO2 nanoparticles investigated by AFM, IR and Raman techniques

“…Tapping mode amplitude modulated AFM [11][12][13][14][15] measurements were acquired with a Multimode V (Veeco Instruments). PointProbe Plus Silicon SPM probes were used, with typical apical diameter of 10 nm.…”

Mechanical properties of rippled structure in suspended stacks of graphene

“…The jump-to-contact occurs, when the cantilever spring constant is lower than the slope of the force-distance curve of the tip-sample interaction, as the tip approaches the sample. 13 As the potential well depth is roughly proportional to the depth of jump-to-contact, the local attractive force F att was defined as force difference in the range of 100 nm in x-axis indicated as black arrow.…”

“…This difference is a well-known general behavior for the static force spectroscopy. 13 When the potential well is deep and the slope of the cantilever spring constant is gentle, that is, ͉⌬F / ⌬z͉ Ͼ k c , the jump-to-contact occurs passing over the potential well region. Then only the steep repulsive force region will be measured.…”

Reduction of Liquid Bridge Force for 3D Microstructure Measurements

“…There are many techniques for measuring surface forces, such as those involving the surface forces apparatus (SFA), atomic force microscopy (AFM), micro cantilever (MC), optical trapping (OT), etc. [13][14][15]. The SFA can directly measure the force between two surfaces in controlled vapors or immersed in liquids.…”