Fabrication of carbon nanotube sensor device by inkjet printing

To overcome the limitation of conventional carbon nanotube fabrication techniques, inkjet printing was directly utilized on a whole wafer. In this work, inkjet printing method was used as a strong technique for the massive production of gas sensor applications. As a single wafer processing, it provided the great potential to fabricate uniform and reproducible single walled carbon nanotube (SWCNT) films on desired positions in terms of electrical characteristics and gas reaction performances. In order to secure good electrical contact between SWCNTs and the metal electrode, SWCNTs were firstly printed on a wafer with insulation layer, and then the metal electrodes were patterned by using lift-off process. The fabricated gaps of the electrodes were 2, 4, and 8 m, respectively. SWCNT films contacted tightly beneath the electrode show low and uniform electrical resistance values of 96-281 and reliable gas detection performances as well. In this work, As-deposited devices exhibit about 3% sensitivities to 100ppb - NO₂ in 10 minutes and increased up to 9% by the annealing treatments at 400degC.