Fast hole transport in polyvinylcarbazole

The initial peak in photocurrent transients observed with Nesaglass-Se-PVK-Au samples is shown to be a space charge limited hole current injected from either Se or Au. The effective hole mobility is of the order 10−3 cm2/Vs at F = 2 × 105 V/cm and influenced by shallow trapping at localized sites of structural origin. The essential conclusion is that fluctuations in the hopping site distances occurring in a molecular solid when going from the crystalline to a disordered phase do not significantly alter its charge transport properties. Time decay of the initial current pulse as well as the tail in the final transit signal are determined by moderately deep trapping and subsequent thermal release.