IMPACT OF THE UNIVERSAL MOBILITY LAW ON POLYCRYSTALLINE ORGANIC DEVICE AND CIRCUIT OPERATION

摘要

We have developed an analytical model for polycrystalline-based organic thin-film transistorsn(OTFTs) that employs, as far as possible, new concepts on carrier injection to the conventionalnpolysilicon model. The drain current equations, both in diffusion and drift regimes, predictnthe voltage and temperature dependencies on the various device and circuit parameters.nInterestingly, upon direct comparison with previously developed disordered model, similaritiesnbetween the two are not thought to be coincidental. The effect of gate voltage on surface potential isnaffected by the Fermi level pinning in the grain boundary, which is assumed to consist of mainlyndisordered material. This work also highlights the problem of using drift mobility, as an organicncircuit design parameter, and consequently alternative quantities are proposed for simpler circuitsnsuch as an inverter. Upon validation of the model, relatively good fits are obtained with thenexperimental data on TIPS-based TFTs. The divergence at low drain voltages are thought to benassociated with short channel and/or high contact resistance effects.