CONTACT ELECTRIFICATION ON THIN SILICON-OXIDE IN VACUUM

We investigated the microscopic dissipation of contact electrified cha rges 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). Charge s with narrower spatial distributions were deposited in smaller amount s in vacuum than in air. Moreover, the deposited charge areas in vacuu m 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.