Single-Walled Carbon Nanotubes as a Chemical Sensor for $\hbox{SO}_{2}$ Detection

Single-walled carbon nanotubes (SWNTs) are Introduced as a chemical sensor for the detection of sulfur dioxide (SO
₂
) molecules. For a single bundle of SWNTs, current-voltage (I-V) curves were measured for a series of different temperatures under adsorption of SO
₂
molecules. The I-V characteristics for a "MAT"-type thin film SWNTs, with respect to the amount of SO
₂
adsorbed, were measured at room temperature and compared directly with O
₂
adsorption. The change in current upon the adsorption of SO
₂
is distinctly higher than that of O
₂
, and is also reversible for adsorption and successive evacuation. Thus, the results strongly suggested that a thin film of SWNTs can be used as a chemical sensor in the nanometer scale devices.