The influence of surface modification on the electrical properties of silicon carbide flakes

Field grading materials with nonlinear behaviour are used in many high voltage applications to avoid any stress concentration that can deteriorate the material performance. In the present work, the current-voltage characteristics of surface functionalized silicon carbide (SiC) flakes were studied and compared to untreated particles. The nonlinear behavior of SiC flakes can be described by transport mechanisms at the grain contact, which can be modeled by Schottky-like barriers. The influence of the organic surface layer on the conduction mechanisms and the corresponding electrical properties were evaluated. In addition, physico-chemical analysis, including X-ray photoelectron spectroscopy (XPS), optical microscopy and zeta-potential measurements were accomplished in order to analyze the surface properties of the SiC flakes, prior to and after surface modification.