title: On the sensing mechanism in carbon nanotube chemiresistors.
abstract: There has been recent controversy whether the response seen in carbon nanotube (CNT) chemiresistors is associated with a change in the resistance of the individual nanotubes or changes in the resistance of the junctions. In this study, we carry out a network analysis to understand the relative contributions of the nanotubes and the junctions to the change in resistance of the nanotube network. We find that the dominant mode of detection in nanotube networks changes according to the conductance level (defect level) in the nanotubes. In networks with perfect nanotubes, changes in the junctions between adjacent nanotubes and junctions between the contacts and the CNTs can cause a detectable change in the resistance of the nanotube networks, while adsorption on the nanotubes has a smaller effect. In contrast, in networks with highly defective nanotubes, the changes in the resistance of the individual nanotubes cause a detectable change in the overall resistance of a chemiresistor network, while changes in the junctions have smaller effects. The combinational effect is also observed for the case in between. The results show that the sensing mechanism of a nanotube network can change according to the defect levels of the nanotubes, which may explain the apparently contradictory results in the literature.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University Of Illinois at Urbana−Champaign, United States. salehikh@illinois.edu
authors.forename: Amin
authors.initials: A
authors.lastname: Salehi-Khojin
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Khalili-Araghi
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Kuroda
authors.forename: Kevin Y
authors.initials: KY
authors.lastname: Lin
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Leburton
authors.forename: Richard I
authors.initials: RI
authors.lastname: Masel
mesh_terms: D017097:Electric Impedance; D037742:Nanotubes, Carbon / Q000737:chemistry*; D012666:Semiconductors; D013499:Surface Properties
chemical_list: D037742:Nanotubes, Carbon