Single-Walled Carbon Nanotubes as a Chemical Sensor for SO2 Detection

Single-walled carbon nanotubes (SWNTs) are Introduced as a chemical sensor for the detection of sulfur dioxide (SO₂) molecules. For a single bundle of SWNTs, current-voltage (I-V) curves were measured for a series of different temperatures under adsorption of SO₂ molecules. The I-V characteristics for a "MAT"-type thin film SWNTs, with respect to the amount of SO₂ adsorbed, were measured at room temperature and compared directly with O₂ adsorption. The change in current upon the adsorption of SO₂ is distinctly higher than that of O₂, 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.