Scanning Kelvin-probe

Maljusch, A., Schdnberger, B., Lindner, A., Stratmann, M., Rohwerder, M., Schuhmann, W. Integrated scanning kelvin probe-scanning electrochemical microscope system Development and first apphcations. 

Recently, scanning Kelvin probes and microprobes, as high-resolution surface analysis devices, have been developed. They allow one to investigate the lateral distribution of the work functions of the surfaces of various phases, including the determination of the potential profiles of metals and semiconductors under very thin films of electrolytic solution, and also of the surface potential map of various polymer- and biomembranes [50-56], The lateral resolution and the sensitivity are in the 100 nm and ImV ranges, respectively [54],... 

Hallam T, Lee M, Zhao N, Nandhakumar I, Kemerink M, Heeney M, McCulloch I, Sirringhaus H (2009) Local charge trapping in conjugated polymers resolved by scanning Kelvin probe microscopy. Phys Rev Lett 103 256803... 

Fig. 12.7. Assessment of channel length of SAP-defined source-drain electrodes (A) top-view environmental scanning electron microscopy (ESEM) image of channel region (B) Scanning Kelvin probe microscopy of...

Scanning force spectroscopy (SFS) Force-distance curves Amplitude-distance curves Phase-distance curves Frequency-distance curves - Kelvin probe spectroscopy - Scanning capacitance spectroscopy Full-resonance spectroscopy (FRS) AFAM resonance spectroscopy (AFAM-RS) Scanning spreading resistance spectroscopy (SSRS)... 

In order to study the effect of the aging after atmospheric exposure on the potential at the inner buried interface of plasma polymer-coated iron, two different plasma-pretreated iron samples were used. For each pretreatment, different TMS plasma polymer thicknesses were studied 20, 50, and 70 nm for Ar + H2 plasma pretreatment, 20, 55, and 115nm for O2 plasma pretreatment. The Scanning Kelvin Probe (SKP) data shown in Figure 33.18 for (Ar + H2) plasma-pretreated and O2 plasma-pretreated samples depicts a correlation between the potential at the inner buried interface and the polymer thickness for respective sample. SKP results showed that the plasma polymer effectively inhibits reoxidation of the interface... 

Figure 33.18 Effect of film thickness on Scanning Kelvin Probe potential.

Many-pass techniques Electric Force Microscopy (EFM) Scanning Capacitance Microscopy (SCaM) Kelvin Probe Microscopy (SKM) DC Magnetic Force Microscopy (DC MFM) AC Magnetic Force Microscopy (AC MFM) Dissipation Force Microscopy-Scanning Surface Potential Microscopy (SSPM) Scanning Maxwell Stress Microscpy (SMMM) Magnetic Force Microscopy (MFM) Van der Waals Force Microscopy (VDWFM)... 

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... 

FIGURE 2.3.12 (a) Schematic diagram of experimental setup for scanning Kelvin probe microscopy (SKPM). (b) Profiles of an L = 5.5 J,m P3HT transistor with Cr electrodes taken at three different temperatures V = 0 V, = -8 V). The inset shows a profile obtained after switching the source and drain contacts on the same TFT with both Cr and Cr-Au contacts Vg = 0 V, = -8 V). (From Burgi, L. et ah, J. Appl. Phys., 94, 6129-6137, 2003. Reprinted with permission. Copyright 2003, American Institute of Physics.)... 

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... 

The scanning Kelvin probe, which measures the Volta potential difference between a specimen and the calibrated sensing probe, is introduced as the only electrochemical technique which allows nondestructive, real-time measurements of electrode potentials at adhesive/metal oxide interfaces in situ, even if they are covered with an adhesive layer. 

I 31 Scanning Kelvin Probe Studies of Ion Transport and De-adhesion Processes... 

As the nature of the electrified interface dominates the kinetics of corrosive reactions, it is most desirable to measure, e.g., the drop in electrical potential across the interface, even where the interface is buried beneath a polymer layer and is therefore not accessible for conventional electrochemical techniques. The scanning Kelvin probe (SKP), which measures in principle the Volta potential difference (or contact potential difference) between the sample and a sensing probe (which may consist of a sharp wire composed of a conducting, stable phase such as graphite or gold) by the vibrating condenser method, is the only technique which allows the measurement of such data and therefore aU modern models which deal with electrochemical de-adhesion reactions are based on such techniques [1-8]. Recently, it has been apphed mainly for the measurement of electrode potentials at polymer/metal interfaces, especially polymer-coated metals such as iron, zinc, and aluminum alloys [9-15]. The principal features of a scanning Kelvin probe for corrosion studies are shown in Fig. 31.1. 

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