Key factors for ultra-high on/off ratio thin-film transistors using as-grown carbon nanotube networks

• Published in: RSC advances Vol. 12; no. 25; pp. 16291 - 16295
• Main Authors: Sun, Yun, Li, Pengpeng, Kauppinen, Esko I, Sun, Dong-Ming, Ohno, Yutaka
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01.06.2022; The Royal Society of Chemistry
• Subjects: Carbon nanotubes; Carrier mobility; Chemistry; Dispersants; electric potential difference; Electronic devices; films (materials); Semiconductor devices; Thin film transistors
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d2ra02088b

Approximately 30% of as-grown carbon nanotube (CNT) networks are metallic, usually leading to a trade-off between carrier mobility and on/off ratio in CNT thin-film transistors (TFTs). Figuring out the key factors of ultra-high on/off ratio in CNT TFTs should be considerably essential for the development of large-scale electronic devices in the future. Here ultra-high on/off ratios of 10 7 -10 8 are realized for CNT TFTs with mobility of ∼500 cm 2 V −1 s −1 . We propose that one of the key factors to achieve the high on/off ratio is a clean CNT thin film without charge traps and doping due to residual dispersant used in conventional solution processes. Moreover, on/off ratio degradation under operation voltage is significantly suppressed by decreasing the diameter of CNTs. A full comprehension about the key factors to achieve ultrahigh on/off ratio thin-film transistors using as-grown CNT networks has been provided, including residual surfactants, chemical doping and CNT diameter.