Investigation and modeling of trap states in ambipolar organic field-effect transistor

Abstract

This work presents a compact analytical model for charge carrier transport in an ambipolar OFET (a-OFET) based on trap-limited conduction (TLC). The model accounts for tail traps in the band gap of the organic semiconductor (OSC) in order to analyse the transistor behaviour in above threshold regime. For the sub-threshold operation of ambipolar OFET, both deep and interface trap states are accounted for, thus accurately describing the transistor behaviour comprising of drift and diffusion elements respectively. A detailed description of surface potential and field-effect mobility for both the electron and hole carriers, in consequence to these trap states has been presented. Individual current components, obtained as a result of modeling tail, deep and interface trap states are combined using the hyperbolic tangent transition function and are in good agreement with the available experimental data. • This work presents modeling of ambipolar OFET using trap-limited conduction (TLC) approach. • Presented work includes modeling of ambipolar current in both above and below threshold regime, by considering tail, deep and interface acceptor and donor-like states in organic semiconductor. • Subthreshold modeling includes both drift and diffusion components. • Dependence of the mobility of electrons and holes on the characteristic temperatures of the distributions of both tail and deep acceptor and donor-like states has been studied. • The model accurately describes the transfer characteristics of ambipolar OFET.