Electrical modes in scanning probe microscopy (SPM) [5] have beco

Electrical modes in scanning probe microscopy (SPM) [5] have become an essential tool in characterizing the electrical properties at the surface of samples, providing spatial resolution and sensitivity at the micro/nanoscale. Several methods have been developed for the measurement

of surface electrical properties and local surface potential, such as electrostatic force microscopy [2, 3] and Kelvin probe force microscopy [6, 7]. The basic principle behind these techniques [5] is applying a Selleck Fludarabine direct current (DC) bias between the conductive probe and the sample to facilitate the recording of variations in the electrostatic force between the probe and sample. These signals are then analyzed in order to interpret the associated surface electrical properties. Jenke GDC-0994 purchase et al. [8] used a Pt-coated Si tip with a radius

Adriamycin research buy of about 380 nm to probe the electrostatic force generated above embedded nanoelectrodes in the vertical (Z) direction. The electrostatic force acting on a grounded conductive tip within an electrostatic field can also be characterized. In this approach, the electrostatic force acting on the atomic force microscopy (AFM) tip comprises Coulombic, induced charge, and image charge forces [9–11]. However, only the Coulombic force is capable of directly revealing the electrical properties of the sample because the two other terms are the result of the AFM tip effect. Kwek et al. [10] glued a charged microparticle to an AFM cantilever to investigate the relative contributions of the Coulombic, induced charge, and image charge forces in the electrostatic force acting on the charged particle; however, the diameter of the charged particle was approximately 105 to 150 μm, which is unsuitable for measurement at the nanoscale. This paper presents a novel microscopy probe for the direct measurement of electrostatic

field (mainly Coulombic force) beside the top electrode of the parallel ADAM7 plate, at a spatial resolution of 250 nm and force resolution of 50 pN(Figure 1). The proposed probe comprises a single 210-nm Teflon nanoparticle (sTNP) attached to the vertex of an insulated Si3N4 AFM tip (sTNP tip) with charge deposited on the sTNP as an electret via contact electrification [2, 12–14]. The parallel plate condenser was fabricated by sputtering layers of Au (30-nm thick) and Ti (20-nm thick) on the top and bottom sides of a 1 × 1 cm glass slide (181 ± 0.25 μm thick). Au was used as the electrode surface and Ti as an adhesion layer. The glass slide was used as the dielectric material. The sTNP tip can be considered a point charge with which to probe the electrostatic force field beside the top electrode of the parallel plate condenser. The electrostatic force acting on the sTNP tip provides direct information related to the local electrostatic field generated in the sample.

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