Surface potential microscopy

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)... 

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... 

H. Kawate, Scanning Surface Potential Microscopy for Local Surface Analysis, M. Eng. Thesis, Tokyo Institute of Technology, Yokohama, 1993... 

Other properties of the surfaces can be analyzed by measuring different forces between sample and tip. Magnetic and electric force microscopy (MFM, EFM) both measure magnetic (or electric) force gradient distribution above the sample surface. Surface potential microscopy measures differences in local surface potential across the sample surface. Finally, electrochemical microscopy measures the surface structure and properties of conducting materials immersed in electrolyte solutions with or without potential control. 

In principle, surface potential microscopy is only usable on conductive substrates. However, the accumulation layer at the insulator-semiconductor interface can be viewed as a conductive layer, whereas the bulk of the semiconductor film is just part of the gap dielectric. In other words, KPFM is capable of imaging the actual potential in the conducting channel with a 100 nm lateral resolution [87-91]. A representative example of the potential profile across the conducting channel is shown in Fig. 9. 

C. Electric Force Microscopy (EFM) and Scanning Surface Potential Microscopy (SSPM)... 

Two nucleation processes important to many people (including some surface scientists ) occur in the formation of gallstones in human bile and kidney stones in urine. Cholesterol crystallization in bile causes the formation of gallstones. Cryotransmission microscopy (Chapter VIII) studies of human bile reveal vesicles, micelles, and potential early crystallites indicating that the cholesterol crystallization in bile is not cooperative and the true nucleation time may be much shorter than that found by standard clinical analysis by light microscopy [75]. Kidney stones often form from crystals of calcium oxalates in urine. Inhibitors can prevent nucleation and influence the solid phase and intercrystallite interactions [76, 77]. Citrate, for example, is an important physiological inhibitor to the formation of calcium renal stones. Electrokinetic studies (see Section V-6) have shown the effect of various inhibitors on the surface potential and colloidal stability of micrometer-sized dispersions of calcium oxalate crystals formed in synthetic urine [78, 79]. 

An unusually extensive battery of experimental techniques was brought to bear on these comparisons of enantiomers with their racemic mixtures and of diastereomers with each other. A very sensitive Langmuir trough was constructed for the project, with temperature control from 15 to 40°C. In addition to the familiar force/area isotherms, which were used to compare all systems, measurements of surface potentials, surface shear viscosities, and dynamic suface tensions (for hysteresis only) were made on several systems with specially designed apparatus. Several microscopic techniques, epi-fluorescence optical microscopy, scanning tunneling microscopy, and electron microscopy, were applied to films of stearoylserine methyl ester, the most extensively investigated surfactant. 

Elatgen et al. [264, 265] have involved surface plasmon microscopy to study the formation of spatiotemporal potential... 

In the present study various surface measurements were made on interfacial lipid films to analyze in more detail the nature of interactions of lipids, Ca2+, ATP, and the glycolate esters. Surface pressure-area and surface potential-area diagrams were obtained on surface films of stearic acid, lecithin, and a mixture of brain lipids with Ca2+, ATP, and the drugs present in the subsolution, individually or in combination. Using radioactive Ca2+, ATP, and drug, quantitative measurements were made on the surface adsorption of these substances to lipid films. In addition, electron microscopy was performed on brain lipid films formed in the presence or absence of Ca2+ and ATP. Our objective was to establish the existence of surface complexes involving these substances with the hope... 

Keywords Atomic force microscopy Charge dissipation Charge domains Electric charges on polymer surfaces Electric field imaging mode Surface potential imaging mode... 

The term electrical force microscopy or electrostatic force microscopy (EFM) is used if the detection of the electrical properties like surface potential or charge is based on a force, leading to a d.c. cantilever bending or to a change in the vibration amplitude or frequency of a vibrating cantilever. 

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