Completely Printed, Flexible, Stable, and Hysteresis-Free Carbon Nanotube Thin-Film Transistors via Aerosol Jet Printing

Nanomaterials offer an attractive solution to the challenges faced for low-cost printed electronics, with applications ranging from additively manufactured sensors to wearables. This study reports hysteresis-free carbon nanotube thin-film transistor (CNT-TFTs) fabricated entirely using an aerosol jet printing technique; this includes the printing of all layers: semiconducting CNTs, metallic electrodes, and insulating gate dielectrics. It is shown that, under appropriate printing conditions, the gate dielectric ink can be reliably printed and yield negligible hysteresis and low threshold voltage in CNT-TFTs. Flexible CNT-TFTs on Kapton film demonstrate minimal variations in performance for over 1000 cycles of aggressive bending tests. New insights are also gained concerning the role of charge trapping in Si substrate-supported devices, where exposure to high substrate fields results in irreversible degradation. This work is a critical step forward as it enables a completely additive, maskless method to fully print CNT-TFTs of direct relevance for the burgeoning areas of flexible/foldable, wearable, and biointegrated electronics.