Trap-modulated mobility of electrons and holes in Teflon FEP

Abstract

The trap-modulated mobilities of electrons and holes in 25-μm Teflon FEP, charged by application of a high dc field at room temperature, are determined from thermally stimulated current (TSC) measurements performed under open-circuit conditions. Use of the TSC method allows one to evaluate approximately the effect of various trapping levels in the material (corresponding to different TSC peaks) on carrier mobility. For example, the first and second above-room-temperature TSC peaks for positive carriers yield mobilities of 10-11 cm2/V sec at 50 and 80 °C, respectively. Similarly, for negative carriers, the second above-room- temperature TSC peak yields a mobility of 10-11 cm2/V sec at 185 °C. The temperature dependence of the mobilities follows an Arrhenius-type behavior with activation energies of 0.7 and 1.0 eV for the positive-carrier peaks and 1.8 eV for the negative-carrier peak.