Electronic Properties of Single-Walled Carbon Nanotube\nNetworks

Abstract

We present a study on the electronic behavior of films of as-prepared and purified single-walled\ncarbon nanotubes (SWNTs) and demonstrate the important role that chemical functionalization plays in\nmodifying their electronic properties, which in turn throws further light on the mechanism of action of SWNT-based sensors. Films of electric arc SWNTs were prepared by spraying, and optical spectroscopy was\nused to measure the effective film thickness. The room-temperature conductivities (σ_RT) of thin films deposited\nfrom as-prepared and purified SWNTs are in the range σ_RT = 250−400 S/cm, and the nonmetallic\ntemperature dependence of the conductivity indicates the presence of tunneling barriers, which dominate\nthe film conductivity. Chemical functionalization of SWNTs with octadecylamine (ODA) and poly(<i>m</i>-aminobenzenesulfonic acid) (PABS) significantly decreases the conductivity; σ_RT = 3 and 0.3 S/cm for\nSWNT-ODA and SWNT-PABS, respectively.