Analytical modeling of the contact resistance in top gate/bottom contacts organic thin film transistors

In this work, an analytical model of the contact resistance in top gate/bottom contacts organic thin film transistors has been derived. It combines both current crowding mechanism and an original model of the vertical accumulation of charges between channel and back electrode.The experimental gate voltage dependency of the contact resistance has been found to be nicely reproduced by this model, without requiring any additional numerical simulations, empirical vertical resistivity formulas or specific injection/transport mechanisms. In addition, the experimental semiconductor thickness and metal work function dependencies of the contact resistance, not considered so far, have been found in excellent agreement with this model.

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► We study contact resistance in OTFT.
► We found that carriers, present over the electrode, impact contact resistances.
► A model is proposed to capture this contribution.
► The model reproduces the gate voltage, the OSC thickness and metal work functions.
► Model is successfully compared with experiments.