FABRICATION OF GAS SENSOR USING SINGLE-WALLED CARBON NANOTUBES DISPERSED IN DICHLOROETHANE

The single-walled carbon nanotube (SWCNT)-field effect transistor (FET) gas sensor was fabricated by spin-coating SWCNTs dispersed in dichloroethane (DCE) solvent on silicon substrate. Raman spectra revealed that walls of the nanotubes were well preserved without much damage during DCE treatment. The sensitivity of the gas sensor was strongly dependent on the series resistance. The sensitivity was maximized in the reasonable contact resistance between nanotubes and electrodes. This was attributed to the suppression of the dark current. The SWCNT gas sensor revealed typical p-type characteristics with respect to NO2 and NH3 gases. The small-bundled SWCNTs increased accessibility of gases to nanotubes and therefore increased the sensitivity of the nanotube gas sensor. The response time was shortened particularly in the case of NO2 gas compared to the previous report.