Spray deposition of highly uniform CNT films and their application in gas sensing

A significant step towards commercialization of novel CNT electronics involves the development of large-area and high-throughput processes for the fabrication of high quality CNT films. In this article, we demonstrate a reliable and reproducible spray deposition process for the fabrication of highly uniform CNT films exhibiting state-of-the-art performance. CNT films with average surface roughness as low as 5.8 nm, and conductivities reaching 4000 S/cm for films of 45 nm thickness, are presented. Incorporating this kind of high quality films as resistive networks for gas detection in ammonia (NH₃) gas sensors, yields device sensitivities reaching 5% at a concentration of 100 ppm for the short exposure interval of only 60 sec. This high NH₃ sensitivity is achieved without any further functionalization of the CNT film, thereby maintaining a simple fabrication process.