Pinch‐Off Mechanism of High‐Gain Organic Transistors with Field Plates: Statistical Analysis, Device Simulations and Compact Modeling

ABSTRACT A field plate is a grounded metal layer underneath the source electrode in thin‐film transistors (TFTs) and was found to significantly reduce pinch‐off voltage and enhance intrinsic gain (up to 320) of inkjet‐printed organic TFTs. The operating mechanism was investigated through automated fabrication and statistical analysis of over 3000 devices with various channel length ( L ) and field plate length ( L fp ​). Crucially, in the saturation regime, transconductance and drain current were governed by L fp ​ rather than L . We propose and validate a new theoretical model, supported by device simulations, which demonstrates that pinch‐off occurs not at the drain or source, but at the edge of the field plate. This novel mechanism explains the observed low pinch‐off voltage and suggests that device performance can be improved through miniaturization, offering a key advantage over conventional high‐gain architectures like source‐gated transistors. In addition, the field plate enables to control pinch‐off voltage simply by layout change, providing functional versatility. Finally, a compact model was developed to facilitate the design of high‐performance printed analog circuits, highlighting the potential of these devices for future flexible electronics.