Atomic Kelvin probe

A further spatially resolved method, also based on work function contrast, is scanning Kelvin probe microscopy (SKPM). As an extended version of atomic force microscopy (AFM), additional information on the local surface potential is revealed by a second feedback circuit. The method delivers information depending on the value (p (p(x) + A x). Here, A(zS(x) is the difference in work function between the sample and the AFM tip and cp(x) is the local electric potential [12]. (p x) itself gives information on additional surface charges due to... 

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... 

Characterizing these many aspects of microstructure is necessary to establish relationships between primary chemical structure, processing, and performance. Currently, the most commonly used methods are scanning probe microscopy techniques such as atomic force microscopy (AFM) or kelvin probe force microscopy... 

Atomic Force Microscopy (AFM), Kelvin Probe Force Microscopy (KFM), and Electric Force Microscopy (EFM)... 

O.A. Semenikhin, L. Jiang, T. lyoda, K. Hashimoto, and A. Fujishima, Atomic force microscopy and Kelvin probe force microscopy evidence of local structural inhomogeneity and nonuniform dopant distribution in conducting polybithiophene. J. Phys. Chem., 100, 18603 (1996). 

A number of methods have applications in studies of corrosion, such as Kelvin probe atomic force and chemical force and scanning tunneling methods. Of these techniques, atomic force microscopy and scanning tunneling microscopy are the most commonly used for roughness measurements. NSOM and SNOM are scanning probe methods used to obtain optical imaging or some form of contrast. 

Defects at the interface most likely play an important role in the delamination process. Unfortunately, the defects in self-assembled films are mostly nanoscopic and can be studied only with atomic force microscopy (AFM) and STM, which require very time-consuming preparation and limit the flexibility of the experiments. Other operation modes such as scanning Kelvin probe force microscopy (SKPFM) [73] will play an important role in future work [74]. 

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]. 

Detail at the atomic level of spatial resolution concerning chemical states and composition is available from STM operated in its various modes—scanning Kelvin probe and scanning tunneling spectroscopy (STS) (Table 2). Single-atom resolution and site identification with these techniques are applicable only to reasonably conductive samples. The alternative is LEIS from which a combination of local atomic structure and quantification of surface composition, especially for light elements, can be obtained [14]. 

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

It had been recognized early that a multitude of forces can act between the tip and the surface and this can be used to probe a variety of surface properties far beyond plain topography. The most prominent example of such a technique is the Kelvin probe force microscopy (KPFM) [122] that has been introduced as atomic force microscopy potentiometry as it allows high-resolution imaging of charges... 

Enevoldsen, G.H., Glatzd, T., Christensen, M.G., Lauritsen, J.V., and Besenbacher, F. (2008) Atomic scale Kelvin probe force microscopy studies of the surface potential variations on the TiO2(110) surface. Phys. Rev. Lett., 100, 236104. 

Nony, L., Foster, A.S., Bocquet, F., and Loppacher, C. (2009) Understanding the atomic-scale contrast in Kelvin probe force microscopy. Phys. Rev. Lett., 103, 036802. 

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