Effect of PGMEA Addition on Zinc‐Tin‐Oxide Thin‐Film Transistor Fabricated by Inkjet‐Printing Process

Zinc‐tin‐oxide (ZTO) thin‐film transistors (TFTs) are made using a low‐viscosity inkjet‐printing process, and their electrical properties are dramatically improved by adding a propylene monomethyl ether acetate (PGMEA) to a solution‐processed ZTO formulation. The addition of 15 wt% PGMEA to the inkjet formulation results in a mobility of 12.29 cm 2 V −1 s −1 , on–off current ratio of 4.72 × 10 8 , threshold voltage of 3.04 V, and subthreshold slope of 0.3 V dec −1 . The TFTs also has stable hysteresis characteristics and improved positive bias stability. These improvements are attributed to the better jetting properties, denser thin film with surface smoothness, and the formation of more metal–oxide networks.