Unveiling the Potential Profile for Channel Access in Staggered Organic Thin-Film Transistors

The device physics of organic thin-film transistors is still an active area of research. Many works focus on the peculiarities of charge transport in organic semiconductors. However, the absence of doping and the use of a thin-film device architecture already distinguish OTFTs from silicon based field-effect transistors. In this study, we reveal that even in the absence of any terminal bias, the intrinsic organic semiconductor in OTFTs draws a significant amount of background charges from the source contact. These injected charges result in the formation of a potential barrier along the access path to the transistor channel, which plays a critical role in current flow. We present an analytical expression for the electrostatic potential along this crucial path, enabling the refinement of existing compact models for OTFTs.