A Fully solution-casted low-voltage driven organic TFT by Floating Film Transfer deposited organic channel on Lanthanum Oxide dielectric film

Abstract

In this work, a self-oriented, fully sol-gel casted cost-effective organic TFT has been fabricated with pristine P3HT polymer as an organic semiconductor channel on high-k Lanthanum Oxide as a gate dielectric. The organic semiconductor channel has been deposited by utilizing a unique floating film transfer (FTM) technique, which has the advantage of minimal wastage, a simple self-oriented organic semiconductor film, enhancing film quality, crystalline properties, grain control, and further improving the carrier transfer phenomenon in the channel. The floating film transfer has the advantage of a simple process, no additional setups, and high-quality organic film over other solution-processed methods (Langmuir Blodgett (LB), Spin Coating, Drop casting, etc.) The fabricated dielectric film passes with a quite smooth surface roughness of 0.926 nm (AFM morphology) and has a high dielectric constant of ~20. Moreover, the fabricated lanthanum oxide film shows a high areal capacitance of 450 nF/cm2, a low leakage current density of ~10 nA/cm2, and a high band gap of 5.14 eV. The device passes with a drain-to-source current of 2.67 μA at- 4V VDS, VGS supply, a threshold potential of 0.47 V, and enhanced mobility of 0.08 cm2/V.s. The organic semiconductor film grown by the FTM method has enhanced crystallinity, oriented grain, and better surface morphology than other solution-processed deposition techniques. The study targets to develop a cost-efficient, simple, low-supply operated portable OTFT for various electronic and sensing applications in the near future. © 2023 IEEE.