Thermally Stimulated Currents in Mylar, High-Field Low-Temperature Case

The thermally stimulated current (TSC) technique has been used to study the release of charge injected into Mylar films with both short (μ sec) and long (10 sec) voltage pulses. The electric field applied across the Mylar is as high as 800 kV cm−1. The TSC spectrum is complex with the peaks at low temperature depending on the type of electrode used and the sign of the voltage pulse. A current reversal exists, which leads to peaks of both signs indicating the possibility that double-injection has occurred. The spectrum at low temperature is characterized by 1/f noise arising possibly from ``slow'' surface states. At high temperatures (410°–450°K) a peak from a deep trapping level occurs with a trap energy estimated to be 1.6–2.0 eV. The spectrum is discussed in terms of possible trap mechanisms.