Electronic carrier motion in PET films

Carrier mobility in polymers has been investigated using various experimental techniques which can be broadly classified into “fast” and “slow” techniques. The distinction is simply made by the time scale of the measurement; microseconds vs. seconds to hours. Reports have shown that these types of techniques yield vastly different mobility values. For example, Hayashi, et al. (1), using 0.1 microsecond pulsed electron beam (EB) excitation, measured electron and hole mobilities of 5 × 10⁻⁵ and 5 × 10⁻⁴ cm²/Vsec respectively for FEP. Gross, et al. (2), using seconds-long EB pulses, measured corresponding values of 10⁻¹⁶ and 2 × 10⁻⁹ cm²/Vsec for this material. In general, the “fast” techniques yield mobility values in the range 10⁻³ to 10⁻⁶ cm²/Vsec while the “slow” techniques yield values in the range 10⁻⁹ to 10⁻¹³ cm²/Vsec.