Fig. 1 Mechanism of electron transfer associated with triboelectric charging67P3-09Poster Award NomineeMechanism of Triboelectric Charging in Fluorine-containing Monolayers Using Amplitude-feedback Frequency Modulated Scanning Force MicroscopyMasahiro Nakayama, Tomoki Misaka, Hiroshi Ohoyama, and Takuya MatsumotoDepartment of Chemistry, Graduate School of Science, Osaka UniversityTriboelectric charging is one of the oldest known charging phenomena. Recently, flexoelectric effect was proposed as the origin of triboelectric charging. The flexoelectric effect is a property of a dielectric material that exhibits a spontaneous electrical polarization induced by a strain gradient and generates strong surface voltage. In this study, we focused on the nanoscale flexoelectric charging in fluorine-containing SAMs (F-DT) due to the strain gradient induced by tip-tapping which was measured as a jump in frequency shift caused by electron transfer due to flexoelectric charging. The frequency shifts of these samples were measured under medium vacuum and room temperature conditions using amplitude-feedback frequency-modulated scanning force microscopy (AM-FM SFM). When the frequency shift was measured, intermittent spikes were observed for F-DT. The spike phenomena were highly dependent on the loading force of cantilevers, and good agreement with the predictions from the flexoelectric charging model. These results strongly suggest that the jump in frequency shift is attributed to the nanoscale flexoelectric effect: the instantaneous surface potential change due to the electron transfer between tip and SAM film induced by flexoelectric effect (Fig. 1).P3-10Quantitative Characterization of Built-in Potential Profile Across GaAs p–n Junctions Using Kelvin Probe Force Microscopy Nobuyuki Ishida and Takaaki ManoCenter for Basic Research on Materials, National Institute for Materials Science (NIMS) Kelvin probe force microscopy (KPFM) is a pivotal technique for measuring the electrostatic potential distribution on a sample surface. It has been extensively used to evaluate semiconductor devices, particularly to observe potential distribution across p-n junctions [1]. However, the magnitudes of the built-in potentials have consistently been smaller than those expected from the actual band structure, primarily due to surface band bending and tip-averaging effect. In this study, we evaluated the quantitative reliability of KPFM by employing an atomic force microscope (AFM) with a qPlus sensor, which is expected to have less tip-averaging effect compared to a cantilever-type AFM and by using a GaAs(110) surface, known for its flat band from the bulk to the surface due to the absence of surface states within the bandgap. KPFM was conducted on the cross section of a GaAs p–n junction, and we demonstrated that using higher-order polynomials instead of a 2nd-order polynomial (quadratic function) in the fitting procedure during CPD derivation improves the accuracy of the CPD measurements [2]. The CPD profiles obtained from these fittings matched well with the line shape of the simulated potential distribution. [1] T. Glatzel et al., Mater. Sci. Eng. B, 102, 138 (2003). [2] N. Ishida and T. Mano, Nanotechnology, 35, 065708 (2024).
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