Printable high-speed thin-film transistor on flexible substrate using carbon nanotube solution

A printable high-speed thin-film transistor (TFT) fabricated on a regular plastic transparency film is proposed. The carrier transport layer of the TFT is an ultrapure carbon nanotube (CNT) thin film of high density (> 1000 CNTs per mum²) formed at room temperature by dispensing a tiny droplet of an electronic-grade CNT solution, which does not contain any surfactant. This CNT-TFT exhibited a high-modulation speed of 312 MHz and a large current-carrying capacity beyond 20 mA. A unique ink-jet printing compatible process demonstrated herein would enable mass production of large-area electronic circuits on any virtually desired flexible substrate at low cost and high throughput.