Kelvin force microscope

While the previously described techniques both require extrapolation of measured data in order to calculate the contact resistance, Kelvin probe force microscopy (KFM, also known as scanning surface potential microscopy or scanning potenti-ometry) can be used to determine the source and drain contributions to the contact resistance directly. In KFM, a conductive atomic force microscope (AFM) tip is scanned over the operational OFET channel twice. On the first pass, the topography... 

Nonnenmacher, M., Oboyle, M., and Wickramasinghe, H.K., Surface investigations with a Kelvin probe force microscope. Ultramicroscopy 42, 268-273, 1992. 

It is also possible to combine AFM with SKP to achieve the capability to map Volta potentials with submicron resolution [90, 120, 121]. The Scanning Kelvin Probe Force Microscope (SKPFM) operates by scanning the topography across a line and then, during a rescan of that line at a fixed distance from the surface. 

O.A. Semenikhin, L. Jiang, T. lyoda, K. Hashimoto, and A. Fujishima, A Kelvin probe force microscopic study of the local dopant distribution in conducting polybithiophene. Electrochim. Acta, 42, 3321 (1997). 

N. Gaillard, M. Gros-Jean, D. Mariolle, F. Beitin, A. Bsiesy, Method to assess the grain crystallographic orientation with a submicronic spatial resolution using Kelvin probe force microscope. Appl. Phys. Lett. 89, 154101 (2006)... 

A modified version of the AC scanning force microscope with a Kelvin probe... 

This simple explanation illustrates how boundary conditions play a crucial role in the capillary force and may lead to nonintuitive observations. This is true for tip dimensions that are of the order of the Kelvin radius, typically below 10 nm. If no special care is taken, atomic force microscope tips are rather rounded with a radius of the order of 10 nm or more, which leads to the maximum of force observed as a function of RH. The position of this maximum strongly depends on the precise shape, explaining the large range of reported values. In their experiments, Kdber et al. used sufficiently small forces to preserve the tip shape down to nanometric dimensions, which was the condition to observe the continuous decrease of the force. 

Other than for electrodes immersed in bulk electrolyte, on electrodes covered by ultrathin layers the electrode potential may differ significantly across the electrode surface. Hence, localised measurements are of interest, being performed by scanning the tip across the sample. This was first applied for organic coated metals where the coating was electrochemically delaminating, driven by corrosion [12-14, 29], Even on the submicron scale the Kelvin probe technique can be applied for such studies, and then based on a modified atomic force microscope, see [34, 35]. Recent developments are the combination of Kelvin probe and SECM [36] and the use of Kelvin probe for hydrogen detection [37]. 

Kelvin Probe Force Microscopy (KPFM or SKPFM) was derived from the development of the atomic force microscope (AFM) al-... 

Figure 3.5.20 Schematic representation of a Kelvin probe force microscope (KPFM).

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