Probe-surface interaction

Gregor MJ, Biome PG, Schofer J, Ulbrich RG (1996) Probe-surface interaction in near-field optical microscopy the nonlinear bending force mechanism. Appl Phys Lett 68 307... 

We would like to stress here the importance of X-ray photoelectron spectroscopy (XPS) for surface characterization, since it analyzes the first 10 or 20 atomic monolayers. It gives information regarding both composition and elemental concentration, as well as the probe-surface interactions. Quite recently [15, 16], this technique allowed the authors to study rhodamine and cyanine dyes physically and/or chemically bound to microcrystalline cellulose. 

In addition to the STM and AFM, the SPM family has expanded to include a whole array of instruments for detecting various probe-surface interactions. Figure 3 shows a comparison of the measurement scale of scanning probe microscopes in relation to other types of microscopy. 

A wide range of techniques can be used to capture the surface roughness of a component using noncontact methods. Some of the more common instruments used to captore topographic data include confocal microscopy, laser triangulation, focus detection, and optical interferometry. A relatively recent branch of microscopy known as scanning probe microscopy (SPM) yields over 20 other instruments which are defined based on what probe-surface interaction they are monitoring. The SPM family is described in more detail elsewhere in this book and will be briefly mentioned in this article. 

Mitchell, J., Stark, S.C., and Strange, J.H. 2005. Probing surface interactions by combining NMR cryoporom-etry and NMR relaxometry. J. Phys. DAppl. Phys. 38 1950-1958. 

Probe size and geometry are essential considerations for resolution. Probe dimensions are a crucial factor to determine the feature size that can be accurately measured with a given technique. Ideally, a probe should be significantly smaller than the feature of interest because a miniaturized probe reduces probe-surface interaction averaging, which can convolute images and decrease resolution. Probe geometry is equally important, especially when measurement quantification relies on equations which assume probe shape. However, limitations of small probes include... 

Scanning ion conductance microscopy, like other SPM techniques, has complex resolution considerations. Resolution is dependent upon probe-surface interaction, as well as probe geometry and probe-surface distance. Image convolutions and artifacts occur as a result of interactions between ion current distribution of the pipette tip and the sample surface. Various models have been proposed to elucidate this behavior. 

Figure 12.8 (a) Sketch of the spot deposition process with a NADIS tip (b) force curve for a loaded cantilever probe with a 400 nm aperture at tip apex. The schematic labeling shows the probe-surface Interaction (a] approach, (b) jump to contact, (c] contact with the surface until a given applied force, (d) adhesion In the presence of a liquid meniscus, and (e) breaking of the liquid meniscus and pulling off of the tip. 

It is possible to perform spectroscopy with SPMs other than the STM. The use of metal-coated cantilevers allows spectroscopic measurements with the AFM. The AFM maps surface topography by monitoring the attractive and/or repulsive probe-surface interactions as a surface is scanned by a cantilever. With a metal-coated cantilever, 7-V curves can be obtained... 

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