Capillary Flow Printing of Submicron Carbon Nanotube Transistors

TL;DR

This paper introduces capillary flow printing (CFP) as a versatile, cleanroom-free method to produce submicron carbon nanotube transistors with high performance and flexibility across various substrates and device architectures.

Contribution

The study demonstrates the first use of CFP to reliably create fully printed submicron CNT transistors without chemical or post-processing steps, enabling scalable flexible electronics.

Findings

Achieved on-currents of 1.12 mA/mm on Si/SiO2

Demonstrated flexible devices with mechanical bending resilience

Validated CFP's versatility across multiple substrates and device types

Abstract

Although printed transistors have a wide range of applications, the limited resolution of printing techniques (10-30 um) has been a barrier to advancement and scaling, particularly down to submicron dimensions. While previous works have shown creative approaches to realizing submicron channel lengths with printing, reliance on chemical processes unique to specific inks or tedious post-processing limit their applicability. Here, we report the use of capillary flow printing (CFP) to repeatably create fully printed submicron carbon nanotube thin-film transistors (CNT-TFTs) without chemical modification or physical manipulation post-printing. The versatility of this printing technique is demonstrated by printing conducting, semiconducting, and insulating inks on several types of substrates (SiO2, Kapton, and paper) and through the fabrication of various TFT device (contacting/gating) architectures. Notably, CFP of these CNT-TFTs yielded on-currents of 1.12 mA/mm when back gated on Si/SiO2, and 490 uA/mm when side gated through ion gel on Kapton, demonstrating the strong transistor performance achievable with CFP. Mechanical bending and sweep rate resilience of devices printed on Kapton show the wide utility of CFP-fabricated devices for flexible applications. This work highlights the ability of CFP as a viable fabrication method for submicron electronics through cleanroom-free printing techniques.