Charge dynamics in irradiated polymers

Recent progress in the field of charge storage and charge transport in polymers irradiated with partially penetrating electron beams is discussed. The analytical model used to describe these phenomena takes the following physical parameters and processes into consideration: charge and energy deposition profiles, ohmic relaxation due to the radiation-induced conductivity, charge drift due to a finite carrier mobility, deep trapping without release, and trap filling due to a finite trap density. The model calculations show the effect of the various parameters on the shape of the charge distribution and on its motion. Experiments with the laser-induced pressure-pulse method on several high-resistivity polymers yield the location of the peak of the charge layers and their shape as function of injected charge density time and annealing conditions. The experimental results are interpreted with an analytical model and realistic values of the required physical parameters. Conclusions about charge dynamics in irradiated polymers are drawn and compared with those of earlier investigations.<
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