The overall device resistance in organic thin film transistor: Application to octithiophene (8T)

Organic thin film transistors were grown with vapor-deposited polycrystalline octithiophene on silicon oxide insulating layers. The performance of an organic thin film transistor may also be affected by morphological details of the interface between the metal and organic-semiconductor near the source and the drain contact. The most important variable contribution to the contact resistance is due to the charge carrier injection at the metal/OSC interface. We have investigated how traps, at the grain boundaries of an organic semiconductor thin film layer placed between the metal electrode and the active layer can contribute to the contact resistance. In this paper we have compared two models, Meyer-Neldel rule-grain boundary trapping model (MNR-GBT) and variable range hopping model (VRH) to extract the overall device resistance of the organic thin film transistor based on octithiophene. We have reproduced very well the output characteristic J(DS)(V-DS) using the good model of overall device resistance. (C) 2011 Elsevier B.V. All rights reserved.