Gas sensing properties of defect-induced single-walled carbon nanotubes

We report a method to induce defects on the surface of single-walled carbon nanotubes (SWNTs) in order to improve the gas-sensing properties of an SWNT-based sensor. In this approach, the surface of the SWNTs is physically modified by thermal treatment at high temperature. The fabricated SWNT-based sensors were subjected to rapid thermal annealing (RTA) over the temperature range of 300-800 °C. After the thermal treatment, the electrical resistances of the defect-induced SWNT sensors were measured and compared with those of pristine SWNT sensors. The gas sensing properties of the defect-induced SWNT sensors upon exposure to various gases such as NO2, NH3, and H2 were measured at room temperature. The thermally treated SWNT-based sensors exhibited much higher sensitivity and recovery than the pristine sensors. These results indicate that the defect-induced SWNTs can improve the performance of SWNT-based sensors.