Steady state and transient photoconduction in poly (N-vinylcarbazole) films

Steady state and transient photoconduction currents under non-uniform illumination by a series of rectangular light pulses have been measured for poly(N-vinylcarbazole) (PVK) films as functions of applied electric field and photon energy. The results show that the carriers photogenerated in the bulk or photo-injected from the metallic electrode are mainly holes, and that the transport is a thermally activated hopping process. The field dependence of the photoconduction current in the visible and infrared regions is attributed to field-assisted photo-injection of holes into the bulk from the metallic electrode by tunneling in a manner similar to the Franz-Keldysh effect.