Carbon nanotube based thin film transistors for gas-sensing and electronic applications

Abstract

The objective of this work is to study single-walled carbon nanotubes (CNTs) based thin film transistors for gas sensing and electronic applications. Single-walled CNTs are promising candidates for future electronic devices because of their excellent electrical, mechanical, optical and chemical properties. CNT based sensors have high potential for large scale adaptation because of its high sensitivity, fast response, and physical/chemical stability. Fabrication of CNT based devices such as thin film transistors (TFTs) by photolithography (PL) can reach high resolution, and meet the requirements of aggressive scaling of physical dimensions like Si-based metal-oxide-semiconductor field-effect transistors (MOSFETs). However, the complicated processes and need of expensive equipment of PL become a major drawback and severely limits its application in various fields. Printing techniques such as inkjet (IJP) and aerosol jet (AJP) printing, possess tremendous advantages in design versatility and operational customization for sensing devices. They are very promising for cost-effective and scalable production of flexible/wearable devices. Fully printed CNT-TFTs are fabricated using AJP and their performance are improved by the optimization of both dielectric printing and CNT network deposition. Fully printed CNT sensors are fabricated using AJP and IJP separately at very low cost. The sensitivity of printed CNT sensors can be highly improved using post drop-cast CNT deposition without any surface functionalization. This work provides key insights for the fabrication and usage of low-cost CNT-TFTs and CNT gas sensors, which has immense potential in flexible and wearable devices.