Contact Electrification on Thin Silicon Oxide in Vacuum

Abstract

We investigated the microscopic dissipation of contact electrified charges on a thin SiO₂ film in vacuum where a thin layer of water may be adsorbed on the surface using an atomic force microscope (AFM). Charges with narrower spatial distributions were deposited in smaller amounts in vacuum than in air. Moreover, the deposited charge areas in vacuum showed no broadening with time after contact electrification. These demonstrate that the rapid surface diffusion of the charges in air may be caused by a water layer adsorbed on the insulator surfaces.