AC response to gas exposure in vertically aligned multiwalled carbon nanotube electrode

vertically aligned multiwalled carbon nanotubes (MWCNTs) as an interdigital electrode were fabricated to investigate AC response to NO₂ gas. The response mechanism was explained in terms of the polarization effect of gases, charge transfer by gas adsorption on CNT electrodes, and field emission current. The response was affected more by gas adsorption than by the polarization effect and field emission effect. We also found that capacitive response and the yield of device production can be significantly improved by a post-heattreatment, which can be explained by the removal of adsorbents such as moisture and/or other functional groups on the CNT surface.