Electrical Properties of Carbon Nanotubes upon Adsorption of Sulfur-containing Molecules

Abstract

Chemical sensors using carbon nanotubes (CNTs) are examined to detect sulfur-containg molecules such as SO2 gas and other organic molecules. First, organic molecules, here dodecanethiol (C12H25SH), butanethiol (C4H9SH), and benzenethiol (C6H5SH), are adsorbed on a single-walled carbon nanotube (SWNT) film, and then we investigate the effect of adsorbed molecules on the electron transport through SWNTs. Sulfur-containing molecules above show strong adsorption on SWNT surface. In case of dodecanethiol, infra-red spectrum reveals CH2 symmetric and asymmetric stretching bands clearly 2700 ~ 3100 cm-1 region. Furthermore, X-ray photoelectron spectroscopy (XPS) also suggests strong interaction between sulfur-containing molecule and CNT surface. From the I-V measurement, current is found to decrease up to 50% from its maximum value as a function of vapor pressure of sulfur-containing molecules.