A method to observe fast dynamic space charge in thin dielectric films

A method is proposed to observe the fast dynamic space charge in thin dielectric film within hundreds of nanoseconds. The method is based on measuring the transient current when a polarized sample is short-circuited. The transient short-circuit current shows damped oscillating feature. For polarized dielectric films, the initial period of damped oscillating current is partly determined by the applied electric field intensity and then the subsequent periods rapidly decrease with the oscillating cycles. The phenomena were demonstrated to be due to space charge formation and fast discharge procedure of space charge by stepwise heat treatment based experiments.