Extracting contact effects in organic field-effect transistors

TL;DR

This paper presents a general method to accurately extract contact effects and true channel mobility in organic field-effect transistors, addressing the influence of contact resistance on device performance across various conditions.

Contribution

It introduces a novel procedure to separate contact and channel contributions in bottom contact OFETs, applicable to both Ohmic and nonlinear charge injection regimes.

Findings

Effective extraction of contact current-voltage characteristics.

Accurate determination of true channel mobility.

Applicability across a broad temperature and gate voltage range.

Abstract

Contact resistances between organic semiconductors and metal electrodes have been shown to play a dominant role in electronic charge injection properties of organic field-effect transistors. These effects are more prevalent in short channel length devices and therefore should not be ignored when examining intrinsic properties such as the mobility and its dependence on temperature or gate voltage. Here we outline a general procedure to extract contact current-voltage characteristics and the true channel mobility from the transport characteristics in bottom contact poly(3-hexylthiophene) field-effect transistors, for both Ohmic and nonlinear charge injection, over a broad range of temperatures and gate voltages. Distinguishing between contact and channel contributions in bottom contact OFETs is an important step toward improved understanding and modeling of these devices.