Electron capture characteristic of trap in PET film under high electrical strength

Abstract

The dynamic properties of electron capture of traps in solid dielectrics under high electrical strength were studied with the surface potential measurement by the authors. A first-order dynamic equation of trapping was derived by considering the detrapping of electrons caused by collision ionization. The theory can qualitatively explain the time characteristic of trapped electrons and the reduction of steady-state values of trapped electrons with electrical strength increasing. The test results confirmed the theoretical analysis. It was shown that the decreasing of the steady-state value was caused by detrapping due to electron collision ionization between the free electrons and the trapped ones rather than by tunnel effect or Poole-Frenkel effect of trapped electrons as usually thought. When the detrapping due to collision ionization reaches a certain degree with the applied electrical strength increasing, the electrical breakdown of dielectrics occurs.