Improving Charge Injection for Organic Field‐Effect Transistor Array via Chemical Functionalized Van der Waals Top‐Contacts

Abstract Efficient charge injection at metal/semiconductor interface is of great importance for high‐performance organic field‐effect transistors (OFETs). In OFETs, top‐contact configuration generally exhibits better injection efficiency but may induces thermal damage to organic layer and is intrinsically difficult to modified with chemisorbs at metal/semiconductor interface. Herein, a versatile, large‐scale and damage‐free metal integration strategy is reported to achieve efficient charge injection in OFETs by applying self‐assembly monolayers (SAMs) functionalized van der Waals (vdW) top‐contact electrodes. Centimeter scale metal electrodes are transferred onto organic single crystal to form OFETs array without residual left. vdW contact provides a clear and atomic sharp interface, and thus the inherent electronic structure and physical properties of the pristine heterostructure interface can be retained. Modifying fluorinated SAMs at metal/semiconductor interface alters the work function of Au by 350 meV, and thus reduces the energy barrier for charge injection. As a result, OFETs array exhibits excellent performance characteristics with an average mobility of 3.6 cm 2 V −1 s −1 , negligible hysteresis and a high on/off ratio above 10 6 on high‐k AlO x dielectric. Organic unipolar inverters based on all vdW contact are also demonstrated. This strategy paves the way for both fundamental study and practical applications of organic electronics.