Analysis and comparison of total resistance models for accurate static modeling of long- and short-channel OTFTs produced with various organic materials

Abstract

In the present study, long- and short-channel organic thin film transistors (OTFTs) produced with various organic semiconductor materials as active layers were fabricated, characterized, and modeled. Two charge transport models, the Meyer-Neldel rule grain boundary-trapping (MNR-GBT) and variable range-hopping models (VRH), were applied to investigate the total device resistance of different types of OTFTs fabricated with various organic semiconductor materials. A generalized method of assessing the current-voltage characteristics of both short- and long-channel OTFTs fabricated with different materials is also presented. All of the devices are described theoretically in terms of their current-voltage characteristics by considering the total resistance's dependence on the gate voltage, which was calculated by substituting the total resistance into the drain current equation. The calculated and measured total resistance and output current-voltage characteristics of each device are presented. Using the best modeled values for the total resistance, the experimental data of output current-voltage characteristics ID(VD) of different kinds of OTFTs are in agreement with those calculated for four different types of OTFTs with long and short channels. The developed model including the total device resistance (according to the Meyer-Neldel rule grain boundary-trapping model) can be applied to long and short-channel devices produced with different materials generalizing all types of OTFTs.