AVS 49th International Symposium
    Nanotubes: Science and Applications Topical Conference Monday Sessions
       Session NT-MoA

Paper NT-MoA5
Investigation on the NO2 Sensitivity Properties of Multi-Wall Carbon Nanotubes Prepared by Plasma Enhanced Chemical Vapor Deposition

Monday, November 4, 2002, 3:20 pm, Room C-209

Session: Nanotubes: Chemical Functionalization, Sensors
Presenter: C. Cantalini, University of L'Aquila, Italy
Authors: C. Cantalini, University of L'Aquila, Italy
L. Valentini, University of Perugia, Italy
I. Armentano, University of Perugia, Italy
J.M. Kenny, University of Perugia, Italy
L. Lozzi, University of L'Aquila, Italy
S. Santucci, University of L'Aquila, Italy
Correspondent: Click to Email
The special geometry and unique properties of carbon nanotubes offer great potential applications, including nanoelectronic devices, energy storage, chemical probes and biosensors.@footnote 1-4@ The effect of gas environment on the electronic properties of carbon nanotubes have recently attracted certain attentions.@footnote 5,6@ In the present work multi-wall carbon nanotubes (MWNTs) deposited by plasma enhanced chemical vapor deposition have been investigated as resistive gas sensors towards NO2. The sensor design is a MWNT serpentine resistor, fabricated by photolithography defining a serpentine Si3N4 path upon silicon, and then growing MWNTs upon the Si3N4 structure. The electrical response has been measured exposing the films to NO2 (5 ppm) at different operating temperatures ranging between 50 and 250 °C. Upon exposure to NO2 the electrical resistance of MWNTs is found to decrease. The nanotube sensors exhibit a fast response and a substantially higher sensitivity than that of existing solid-state sensors at room temperature. Sensor reversibility is achieved by slow recovery under ambient conditions or by a higher recovery heating to 200 °C. Experimental findings revealed the chemisorption of oxidizer gas upon the surface of the NWNTs. Hence it appears that p-type semiconductor behavior is present in the MWNTs. @FootnoteText@@footnote 1@Dresselhaus M S et al. 1996 Scienceof Fullenrenes and Carbon Nanotubes (New York:Academic) @footnote 2@Ebbesen T (ed) 1997 Carbon Nanotube: Preparation andProperties (Boca Raton, FL: CRC Press) @footnote 3@Saito R et al. 1998 PhysicsProperties of Carbon Nanotubes (New York: WorldScientific) @footnote 4@Lu J P et al. 1998 Int. J. High Electron. Syst. 9 101@footnote 5@Kong J et al. 2000 Science 287 622 @footnote 6@Collins P G et al. 2000 Science 287 1801 .