On the role of field-induced polarization in the surface electrification of insulators

The single-point electrification of silicon dioxide, sapphire, and silicon nitride has been studied using noncontact scanning force potentiometry. For all these insulators, the potentiometric signal showed a multicomponent decay which was rapid compared to the charge retention characteristics of the bulk material. The magnitude of the initial signal varied linearly with contact bias voltage: a change from positive to negative bias reversed the sign of the signals without changing their magnitude or decay dynamics. These features suggest that the initial increase in surface potential in single contact electrification may be due to field-dependent polarization rather than net charge transfer. (C) 1996 American Institute of Physics.