Proximity effects of negative charge groups contact-electrified on thin silicon oxide in air

Abstract

We investigated proximity effects of negative charge groups contact‐electrified on a thin silicon oxide in air with an initial separation (L) less than a few micrometers using a modified atomic force microscope. As a result, we found the following phenomena. Even for L∼2.0 μm, distributions of two negative charge groups approach each other with time after contact electrification, though this feature is contrary to the expected recession due to the Coulomb repulsive force. For less than L∼1.6 μm, each stable state joins in one negative charge group. These proximity effects seem to be induced by the interplay of the Coulomb repulsive force and the surface diffusion of charges.