title: Effect of surface wettability properties on the electrical properties of printed carbon nanotube thin-film transistors on SiO2/Si substrates.
abstract: The precise placement and efficient deposition of semiconducting single-walled carbon nanotubes (sc-SWCNTs) on substrates are challenges for achieving printed high-performance SWCNT thin-film transistors (TFTs) with independent gates. It was found that the wettability of the substrate played a key role in the electrical properties of TFTs for sc-SWCNTs sorted by poly[(9,9-dioctylfluorene-2,7-diyl)-co-(1,4-benzo-2,1,3-thiadiazole)] (PFO-BT). In the present work we report a simple and scalable method which can rapidly and selectively deposit a high concentration of sc-SWCNTs in TFT channels by aerosol-jet-printing. The method is based on oxygen plasma treatment of substrates, which tunes the surface wettability. TFTs printed on the treated substrates demonstrated a low operation voltage, small hysteresis, high mobility up to 32.3 cm(2) V(-1) s(-1), and high on/off ratio up to 10(6) after only two printings. Their mobilities were 10 and 30 times higher than those of TFTs fabricated on untreated and low-wettability substrates. The uniformity of printed TFTs was also greatly improved. Inverters were constructed by printed top-gate TFTs, and a maximum voltage gain of 17 at Vdd = 5 V was achieved. The mechanism of such improvements is that the PFO-BT-functionalized sc-SWCNTs are preferably immobilized on the oxygen plasma treated substrates due to the strong hydrogen bonds between sc-SWCNTs and hydroxyl groups on the substrates.
authors.affiliation: Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , No. 398 Ruoshui Road, Science and Education Innovation District (SEID), Suzhou Industrial Park, Suzhou, Jiangsu Province 215123, People's Republic of China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.forename: Jianwen
authors.initials: J
authors.lastname: Zhao
authors.forename: Wenya
authors.initials: W
authors.lastname: Xu
authors.forename: Long
authors.initials: L
authors.lastname: Qian
authors.forename: Shuhong
authors.initials: S
authors.lastname: Nie
authors.forename: Zheng
authors.initials: Z
authors.lastname: Cui