Dielectric-Relaxation Currents in Insulators

Abstract

If at low temperatures a voltage bias is applied to an insulator containing traps, it is shown that the current flowing in the insulator is a non-steady-state dielectric-relaxation current (DRC) which is always greater than the steady-state current. If the sample is held at low temperatures, the DRC will prevail essentially indefinitely. However, if the temperature of the sample is raised, then over some narrow interval of temperature, centered around a temperature, say, $T_m$, the insulator and hence the current through the system relax quickly to the steady-state condition. Thus, at $T_m$, the DRC-vs-temperature characteristic exhibits a pronounced maximum. $T_m$ is related to the depth of the trapping level below the bottom of the conduction band of the insulator, and the area under the DRC-vs-temperature characteristic is directly proportional to the trapping density.