Gas detection mechanism for single-walled carbon nanotube networks*

We study field-effect transistors fabricated with carbon nanotube (CNT) networks to determine whether the gas sensing mechanism is due to molecules adsorbed on the nanotubes, or changes at the interface between the nanotubes and the contacts. Our previous work showed that in devices made with isolated CNT, the response to nitrogen dioxide was mainly due to the contact interfaces [1]. Here, we focus on CNT networks and use SU-8 layers patterned with e-beam lithography to passivate the contact interfaces, while leaving the network exposed. We look to investigate possible differences in sensing mechanism for devices made with isolated tubes versus networks. \\[4pt] [1] J. Zhang, A. Boyd, A. Tselev, M. Paranjape, and P. Barbara, \textit{Mechanism of NO}$_{2}$\textit{ detection in carbon nanotube field effect transistor chemical sensors}, Applied Physics Letters \textbf{88,} 123112-123115 (2006)