Chlorite is a layered silicate mineral group of importance in geology, agriculture, and in the processing of mineral resources. A more detailed analysis of the surface charge of chlorite minerals is important in order to improve our fundamental understanding of such particle structures and their behavior in suspension. In this study, the anisotropic surface charging of chlorite has been established using Atomic Force Microscopy surface-force measurements with a silicon nitride tip. The surface-charge densities and surface potentials at the chlorite basal-plane surfaces and edge surface were obtained by fitting force curves with the Derjaguin-Landau-Verwey-Overbeek theoretical model. The results show that at pH 5.6, 8.0, and 9.0 the chlorite mica-like face is negatively charged with the isoelectric point (IEP) less than pH 5.6. In contrast, the chlorite brucite-like face is positively charged in this pH range and the IEP is greater than pH 9.0. The surface charging of the chlorite edge surface was found to be pH-dependent with the IEP occurring at pH 8.5, which is slightly greater than the edge surfaces of talc and muscovite due to the larger content of magnesium hydroxide at the chlorite edge surface. Findings from the present research are expected to provide a fundamental foundation for the analysis of industrial requirements, e.g. collector adsorption, slime coating, and particle interactions in the area of mineral-processing technology.

Sideband Kelvin probe force microscopy (KPFM) uses the intermodulation of an electrostatic drive force and a mechanical drive force to upconvert the electrostatic frequency to the first flexural resonance, where the high-quality factor of the resonance yields a more sensitive measurement. The sideband KPFM signal is calculated using a local interaction between the tip apex and the sample, rather than a total interaction between the cantilever and the sample, improving the spatial resolution over other technique variations. This paper covers the sideband KPFM details, including trade-offs and imaging of semi-fluorinated alkanes, such as F14H20, and self-assembled molecular nanostructures.

In this study, resistive switching (RS), polarization switching, and charge distribution under DC bias in undoped ZnO thin films are studied by applying scanning probe microscopy (SPM) techniques on the same location. The techniques include Piezoresponce Force Microscopy, Kelvin Probe Force Microscopy, and Conductive Atomic Force Microscopy. The effects of oxygen partial pressure during the film deposition are also investigated. The results show that high resistance state (HRS) is accompanied by the polarization switching and charges storage. By comparing the SPMs results from the same location, it is found that the oxygen partial pressure during film deposition is an important factor over the holes injection during the poling processes in the HRS. On the other hand, the low resistance state (LRS) may be dominated by the electrons injection. Based on these findings, the energy band diagrams in the Pt-tip/ZnO-film/Pt-bottom-electrode structure with the applications of the external biases are illustrated schematically. This study also proposes a more persuasive mechanism of RS in ZnO films.

Hybrid organic/inorganic nanostructures are engineered to function as two terminal devices with enhanced functionality. The devices are the building blocks for designing hybrid organic/inorganic circuits in the nanoscale. In our work, we have demonstrated the sensing capabilities of polymer nanocomposite thin films for designing nanoweb devices towards detection of biomolecules. Biomolecules with surface charge such as troponin-T were detected on this device by interfacing them with the polymer/metal composites. The change in electrical properties due to modulation in charge transport at the crossbar junction was identified as the measured electrical signal for designing switch based sensors. Nanotextured surface offers strong charge carrier transport and hence enhances the strength of the detected signal. The antibodyantigen interactions at the junction effectively modulate the charge transfer kinetics and modify the junction characteristics due to the surface potential associated with the organic molecules. The net change in surface charge can be measured either as changes in the diode current in the two terminal configuration or as changes in the source- drain current in the three terminal configuration. Detection sensitivity in the order of pg/mL was targeted by measuring the voltammetric current response (in microamperes).

The goal of this article is first to review the charging effects occurring when an insulating material is subjected to electron irradiation in a scanning electron microscope (SEM) and next their consequences from both scanning electron microscopy and electron probe microanalysis (EPMA) points of view. When bare insulators are observed, the so-called pseudo mirror effect leads to an anomalous contrast and also to an erroneous surface potential, VS, measurement when a Duane–Hunt limit (DHL) method is used. An alternative possibility is to use an electron toroidal spectrometer (ETS), specially adapted to a SEM, which directly gives the VS value. In the case of a bulk specimen coated with a grounded layer, although the layer prevents external effects of the trapped charge, the electric field beneath the coating is reinforced and leads to loss of ionizations that reduces the number of generated X-ray photons. To take into account both effects mentioned above, whether the studied insulator is coated or not, a method is proposed to deduce the trapped charge inside the insulator and the corresponding internal or external electric field.