Numerical Modelling of Carrier Transport in Organic Field Effect Transistors

Organic field effect transistors (OFETs), used in the fabrication of nano-sensors, are one of the most promising devices in the field of organic electronics, because of their light weight, flexible and low fabrication cost. However, the optimization of such OFETs is still in an early stage due to the very limited analytical as well as numerical models presented in the literature. This research presses to demonstrate a numerical carrier transport model based on finite element method (FEM), to investigate the I-V characteristic of OFETs. Two various organic semiconductor materials have been included in the study, polyaniline and pentacene, where a micro-scale as well as a nano-scale models have been presented. OFETs have been studied in terms of channel length, dielectric thickness, and doping level impact. We nominated the threshold voltage, the on/off current ratio, the sub threshold swing, and the field effect mobility’s as the main output evaluating parameters. The numerical model has shown the criticality of the doping effect on tuning the device flowing drain current, to exceed 300 μA saturation current, along with threshold voltage of -0.1 V under a channel length of 30 nm. Additionally, the study highlights the effectiveness of the polyaniline over pentacene as nano-channel length OFET, due to the boosted conductivity of polyaniline with respect to pentacene.