The nature of the plateau on the time-of-flight curves in molecularly doped polymers

The transient current curves for a polar molecularly doped polymer were compared for the nearsurface and bulk generation of charge carriers. The horizontal plateau on the first curve was expected to transform into a tilted straight line under the quasiequilibrium transport conditions, but it did not. Instead, for bulk generation, the curve was a hyperbola, on which the slope decreased almost sevenfold during the existence of the plateau. This behavior points to nonequilibrium charge carrier transport. The appearance of a plateau in our case is explained by the effect of the defective surface layer, as indicated in our previous communications.