Influence of Electrode Thickness on Contact Resistance in Solution-Processed Organic Field-Effect Transistors

The diminution of contact resistance in organic field-effect transistors (OFETs) has become one of the most significant areas of research in the development of OFET technology toward real application. In addition to contact and material engineering, the thickness of the source-drain (SD) electrode serves a pivotal role in determining the contact resistance in solution-processed bottom-gate bottom-contact (BGBC) OFETs. This study explores the impact of morphological disorder at the metal-semiconductor (M-S) interface, arising due to the thickness of SD electrodes on contact resistance, particularly in solution-processed BGBC OFETs. A 20-fold reduction in contact resistance and 2-fold increase in mobility is observed in devices with a 20 nm SD electrode compared to those with an 80 nm SD electrode. Furthermore, TCAD simulations incorporating mobility modeling in disordered channel regions provide insights into the underlying physics governing contact resistance variations.