Gas sensors for NO2 detection were fabricated using printed multiwalled carbon nanotubes (MWCNTs) before and after electric field surface treatment. Printed MWCNTs showed an increase of sensitivity upon exposure to NO, and field emission due to vertical alignment and protrusion of CNTs from surface layer after electric field surface treatment. Electron field emission plays a role recovery when exposed to gas molecules in CNT. A Fast recovery time of the printed MWCNT gas sensor was obtained by ohmic heat with a partial field emission effect at room temperature. (c) 2006 Elsevier B.V. All rights reserved.