About charge carrier mobility in common insulating polymers

Abstract

Numerical calculations have been performed on the time of flight transients predicted by a newly developed model describing consistently the radiation-induced conductivity of common insulating polymers under both pulsed and continuous irradiation. The model differs substantially from the conventional multiple trapping formalism based on an exponential trap distribution by the presence of additional deep traps distributed in energy or even external deep traps allowing no thermal detrapping (the so-called sinks). This circumstance complicates the definition of the main transport characteristic, the drift mobility, so familiar in Gaussian (normal) or dispersive transport. An analysis of the current transients has been done in a range of fields (107–109 V/m), decay times (10−9–104 s), and not too thin sample thicknesses (2–20 μm). No operational procedure for the determination of a unique time of flight could be found, and therefore, information about charge carrier transport in common insulating polymers must be obtained through numerical calculations. All previous studies on this subject have been critically reviewed.